An eye care professional is an individual who provides a service related to the eyes or vision. It is a general term that can refer to any healthcare worker involved in eye care, from one with a small amount of post-secondary training to practitioners with a doctoral level of education.
Types of eye care professionals
Current terminology
* Ophthalmologist – A medical doctor (MD) who specializes in surgical eye care. In the US, this often requires four years of college, four years of medical school, and four to six more years of residency, internship, and/or fellowship and sub specialty training.
* Ophthalmic medical practitioner – A medical doctor (MD) who specialises in ophthalmic conditions but who has not completed a specialisation in ophthalmology. (term used in the UK).
* Optometrist – Diagnoses common eye diseases and disorders as well as refractive vision correction. In some countries they can treat with a limited number of pharmaceuticals. In a small number of countries they do minor surgery within the limits of what General Practitioners do, although sometimes the scope of this is disapproved by ophthalmologists.
o In most countries, optometry is either a 4 year or 5 year college degree and they are not classified as Doctors (except in the Philippines).
o In the USA, the standard education is four years of college and four years of optometry school at an accredited Doctor of Optometry (OD) program. An additional one to two years of residency, internship, fellowship and/or specialty training is required for qualification in certain positions. Many US states forbid optometrists from advertising specialties, but each state allows optometrists to treat common eye problems and prescribe certain pharmaceuticals.
* Orthoptist – Specializes in diagnosis and management of ocular motility, amblyopia and binocular vision disorders, as outlined by the International Orthoptic Association. They also assist ophthalmologists in surgery and in most countries are accredited ocular sonographers.[1]
o In many countries including the USA, the standard education is three years of college, plus two years in post graduate college.
o In other countries (such as Australia), it is a 4 year Master's degree.
* Ocularist – Specialize in the fabrication and fitting of ocular prostheses for people who have lost eyes due to trauma or illness.
* Optician – Specializes in the fitting and fabrication of ophthalmic lenses, spectacles, contact lenses, low vision aids and ocular prosthetics. They may also be referred to as an "optical dispenser", "dispensing optician", "ophthalmic dispenser". The prescription for the corrective lenses must be supplied by an ophthalmologist, optometrist or in some countries an orthoptist. This is a regulated profession in most jurisdictions.
* Ophthalmic Medical Personnel – A collective term for allied health personnel in ophthalmology. It is often used to refer to specialized personnel (unlike ocularists or opticians).
o In many countries these allied personnel may just be known as an "ophthalmic assistant". Their training is usually combined with a two or three year applied science degree and they assist an ophthalmologist or orthoptist in the hospital or clinic with vision testing.
o In the USA the Joint Commission on Allied Health Personnel in Ophthalmology administers OMP certifications:
1. Certified Ophthalmic Assistant (COA) – entry level
2. Certified Ophthalmic Technician (COT) – intermediate level
3. Certified Ophthalmic Medical Technologist (COMT) – advanced level
[edit] Older terminology
* Oculist – Either an ophthalmologist or optometrist.
* Vision therapist – Usually either an orthoptist or optometrist. Works with patients that require vision therapy, such as low vision patients.
Most eye care professionals do not practice iridology, citing a significant lack of scientific evidence for the practice.
[edit] The distinction between ophthalmologist, optometrist and orthoptist
The American Academy of Ophthalmology describes an ophthalmologist as follows:
A medical doctor who specializes in all aspects of eye care including diagnosis, management, and surgery of ocular diseases and disorders.
An optometrist is defined by the World Council of Optometry (a member of the World Health Organisation) as follows:
Optometry is a healthcare profession that is autonomous, educated, and regulated (licensed/registered), and optometrists are the primary healthcare practitioners of the eye and visual system who provide comprehensive eye and vision care, which includes refraction and dispensing, detection of disease in the eye, and the rehabilitation of conditions of the visual system.
The World Health Organisation defines the eyecare work of an orthoptist as:
The study and treatment of defects in binocular vision resulting from defects in the optic musculature or of faulty visual habits. It involves a technique of eye exercises designed to correct the visual axes of eyes not properly coordinated for binocular vision.[2]
Two important distinctions are evident in these definitions:
* Ophthalmologists are medical doctors and have attended medical school and specialize in surgical as well as medical care of the eye, optometrists are eyecare professionals who have attended optometry school that specialize in the refractive and primary medical care of the eye and vision, while orthoptists are eyecare professionals who have attended orthoptic school and specialize in the binocular vision and pre/post surgical care of strabismus patients.
* Second, ophthalmologists are responsible for surgical treatment or ocular disease. Optometrists "provide comprehensive eye and vision care, which includes refraction and detection/diagnosis and limited management of disease in the eye." Optometrists refer to ophthalmologists patients requiring treatments such as ocular surgery, intraocular injections, and lasers. Orthoptists primarily work alongside ophthalmologists to co-manage binocular vision treatment, but also often do comprehensive eye and vision testing.
There are also important similarities. Both optometrists and ophthalmologists treat patients with medications, optical aids and eye exercises; orthoptists treat using optical aids and eye exercises.[3] All perform screenings for common ocular problems affecting children (such as amblyopia and strabismus) and the adult population (such as cataracts, glaucoma, and diabetic retinopathy).[4] All are required to participate in ongoing continuing education courses to maintain licensure and stay current on the latest standards of care.
[edit] International organizations
* International Council of Ophthalmology
* World Council of Optometry. WCO represents optometrists in 40 countries.
* International Orthoptic Association. IOA represents orthoptists in 20 countries.
[edit] Organisations by country
* American Optometric Association
* American Academy of Optometry
* American Association for Pediatric Ophthalmology and Strabismus
* American Orthoptic Association
* American Society of Ocularists
* American Academy of Ophthalmology
* Orthoptic Association of Australia
* British Optical Association
* Royal College of Ophthalmologists
* College of Optometrists
* College of Optometrists in Vision Development
* Joint Commission on Allied Health Personnel in Ophthalmology
* Opticians Association of Canada
* Optometric Extension Program
* Worshipful Company of Spectacle Makers
* The Association of Optometrists, Ireland
* Association of British Dispensing Opticians
Wednesday, October 28, 2009
EYE
Eyes are organs that detect light, and send electrical impulses along the optic nerve to the visual and other areas of the brain. Complex optical systems with resolving power have come in ten fundamentally different forms, and 96% of animal species possess a complex optical system.Image-resolving eyes are present in cnidaria, molluscs, chordates, annelids and arthropods.
The simplest "eyes", such as those in unicellular organisms, do nothing but detect whether the surroundings are light or dark, which is sufficient for the entrainment of circadian rhythms. From more complex eyes, retinal photosensitive ganglion cells send signals along the retinohypothalamic tract to the suprachiasmatic nuclei to effect circadian adjustment.
Complex eyes can distinguish shapes and colors. The visual fields of many organisms, especially predators, involve large areas of binocular vision to improve depth perception; in other organisms, eyes are located so as to maximise the field of view, such as in rabbits and horses, which have monocular vision.
The first proto-eyes evolved among animals 540 million years ago, about the time of the Cambrian explosion.[citation needed] The last common ancestor of animals possessed the biochemical toolkit necessary for vision, and more advanced eyes have evolved in 96% of animal species in 6 of the thirty-plus[note 1] main phyla.[1] In most vertebrates and some molluscs, the eye works by allowing light to enter it and project onto a light-sensitive panel of cells, known as the retina, at the rear of the eye. The cone cells (for color) and the rod cells (for low-light contrasts) in the retina detect and convert light into neural signals for vision. The visual signals are then transmitted to the brain via the optic nerve. Such eyes are typically roughly spherical, filled with a transparent gel-like substance called the vitreous humour, with a focusing lens and often an iris; the relaxing or tightening of the muscles around the iris change the size of the pupil, thereby regulating the amount of light that enters the eye,[3] and reducing aberrations when there is enough light.[4]
The eyes of cephalopods, fish, amphibians and snakes usually have fixed lens shapes, and focusing vision is achieved by telescoping the lens — similar to how a camera focuses.[5]
Compound eyes are found among the arthropods and are composed of many simple facets which, depending on the details of anatomy, may give either a single pixelated image or multiple images, per eye. Each sensor has its own lens and photosensitive cell(s). Some eyes have up to 28,000 such sensors, which are arranged hexagonally, and which can give a full 360-degree field of vision. Compound eyes are very sensitive to motion. Some arthropods, including many Strepsiptera, have compound eyes of only a few facets, each with a retina capable of creating an image, creating vision. With each eye viewing a different thing, a fused image from all the eyes is produced in the brain, providing very different, high-resolution images.
Possessing detailed hyperspectral color vision, the Mantis shrimp has been reported to have the world's most complex color vision system.[6] Trilobites, which are now extinct, had unique compound eyes. They used clear calcite crystals to form the lenses of their eyes. In this, they differ from most other arthropods, which have soft eyes. The number of lenses in such an eye varied, however: some trilobites had only one, and some had thousands of lenses in one eye.
In contrast to compound eyes, simple eyes are those that have a single lens. For example, jumping spiders have a large pair of simple eyes with a narrow field of view, supported by an array of other, smaller eyes for peripheral vision. Some insect larvae, like caterpillars, have a different type of simple eye (stemmata) which gives a rough image. Some of the simplest eyes, called ocelli, can be found in animals like some of the snails, which cannot actually "see" in the normal sense. They do have photosensitive cells, but no lens and no other means of projecting an image onto these cells. They can distinguish between light and dark, but no more. This enables snails to keep out of direct sunlight. In organisms dwelling near deep-sea vents, compound eyes have been secondarily simplified and adapted to spot the infra-red light produced by the hot vents - in this way the bearers can spot hot springs and avoid being boiled alive.[7]
[edit] Evolution
Main article: Evolution of the eye
Diagram of eye evolution.svg
The common origin (monophyly) of all animal eyes is now widely accepted as fact based on shared anatomical and genetic features of all eyes; that is, all modern eyes, varied as they are, have their origins in a proto-eye believed to have evolved some 540 million years ago.[8][9][10] The majority of the advancements in early eyes are believed to have taken only a few million years to develop, as the first predator to gain true imaging would have touched off an "arms race".[11] Prey animals and competing predators alike would be forced to rapidly match or exceed any such capabilities to survive. Hence multiple eye types and subtypes developed in parallel.
Eyes in various animals show adaption to their requirements. For example, birds of prey have much greater visual acuity than humans, and some can see ultraviolet light. The different forms of eye in, for example, vertebrates and mollusks are often cited as examples of parallel evolution, despite their distant common ancestry.
The earliest eyes, called "eyespots", were simple patches of photoreceptor cells, physically similar to the receptor patches for taste and smell. These eyespots could only sense ambient brightness: they could distinguish light and dark, but not the direction of the lightsource.[12] This gradually changed as the eyespot depressed into a shallow "cup" shape, granting the ability to slightly discriminate directional brightness by using the angle at which the light hit certain cells to identify the source. The pit deepened over time, the opening diminished in size, and the number of photoreceptor cells increased, forming an effective pinhole camera that was capable of slightly distinguishing dim shapes.[13]
The thin overgrowth of transparent cells over the eye's aperture, originally formed to prevent damage to the eyespot, allowed the segregated contents of the eye chamber to specialize into a transparent humour that optimized colour filtering, blocked harmful radiation, improved the eye's refractive index, and allowed functionality outside of water. The transparent protective cells eventually split into two layers, with circulatory fluid in between that allowed wider viewing angles and greater imaging resolution, and the thickness of the transparent layer gradually increased, in most species with the transparent crystallin protein.[14]
The gap between tissue layers naturally formed a bioconvex shape, an optimally ideal structure for a normal refractive index. Independently, a transparent layer and a nontransparent layer split forward from the lens: the cornea and iris. Separation of the forward layer again forms a humour, the aqueous humour. This increases refractive power and again eases circulatory problems. Formation of a nontransparent ring allows more blood vessels, more circulation, and larger eye sizes.[14]
[edit] Types of eye
Nature has produced ten different eye layouts — indeed every way of capturing an image has evolved at least once in nature, with the exceptions of zoom and Fresnel lenses. Eye types can be categorized into "simple eyes", with one concave chamber, and "compound eyes", which comprise a number of individual lenses laid out on a convex surface.[1] Note that "simple" does not imply a reduced level of complexity or acuity. Indeed, any eye type can be adapted for almost any behaviour or environment. The only limitations specific to eye types are that of resolution — the physics of compound eyes prevents them from achieving a resolution better than 1°. Also, superposition eyes can achieve greater sensitivity than apposition eyes, so are better suited to dark-dwelling creatures.[1] Eyes also fall into two groups on the basis of their photoreceptor's cellular construction, with the photoreceptor cells either being cilliated (as in the vertebrates) or rhabdomic. These two groups are not monophyletic; the cnidaira also possess cilliated cells, [15] and some annelids possess both.[16]
[edit] Simple eyes
Simple eyes are rather ubiquitous, and lens-bearing eyes have evolved at least seven times; in vertebrates, cephalopods, annelids, crustacea and cubozoa.[17]
[edit] Pit eyes
Pit eyes, also known as stemma, are eye-spots which may be set into a pit to reduce the angles of light that enters and affects the eyespot, to allow the organism to deduce the angle of incoming light.[1] Found in about 85% of phyla, these basic forms were probably the precursors to more advanced types of "simple eye". They are small, comprising up to about 100 cells covering about 100 µm.[1] The directionality can be improved by reducing the size of the aperture, by incorporating a reflective layer behind the receptor cells, or by filling the pit with a refractile material.[1]
[edit] Pinhole eye
Nautiluses bear a pinhole eye
The pinhole eye is an "advanced" form of pit eye incorporating several improvements, most notably a small aperture (which may be adjustable) and deep pit. It is only found in the nautiloids.[1] Without a lens to focus the image, it produces a blurry image, and will blur out a point to the size of the aperture. Consequently, nautiloids can't discriminate between objects with an angular separation of less than 11°.[1] Shrinking the aperture would produce a sharper image, but let in less light.[1]
[edit] Spherical lensed eye
The resolution of pit eyes can be greatly improved by incorporating a material with a higher refractive index to form a lens, which may greatly reduce the blur radius encountered — hence increasing the resolution obtainable.[1] The most basic form, still seen in some gastropods and annelids, consists of a lens of one refractive index. A far sharper image can be obtained using materials with a high refractive index, decreasing to the edges — this decreases the focal length and thus allows a sharp image to form on the retina.[1] This also allows a larger aperture for a given sharpness of image, allowing more light to enter the lens; and a flatter lens, reducing spherical aberration.[1] Such an inhomogeneous lens is necessary in order for the focal length to drop from about 4 times the lens radius, to 2.5 radii.[1]
Heterogeneous eyes have evolved at least eight times — four or more times in gastropods, once in the copepods, once in the annelids and once in the cephalopods.[1] No aquatic organisms possess homogeneous lenses; presumably the evolutionary pressure for a heterogeneous lens is great enough for this stage to be quickly "outgrown".[1]
This eye creates an image that is sharp enough that motion of the eye can cause significant blurring. To minimize the effect of eye motion while the animal moves, most such eyes have stabilizing eye muscles.[1]
The ocelli of insects bear a simple lens, but their focal point always lies behind the retina; consequently they can never form a sharp image. This capitulates the function of the eye. Ocelli (pit-type eyes of arthropods) blur the image across the whole retina, and are consequently excellent at responding to rapid changes in light intensity across the whole visual field — this fast response is further accelerated by the large nerve bundles which rush the information to the brain.[18] Focusing the image would also cause the sun's image to be focused on a few receptors, with the possibility of damage under the intense light; shielding the receptors would block out some light and thus reduce their sensitivity.[18] This fast response has led to suggestions that the ocelli of insects are used mainly in flight, because they can be used to detect sudden changes in which way is up (because light, especially UV light which is absorbed by vegetation, usually comes from above).[18]
[edit] Weaknesses
One weakness of this eye construction is that chromatic aberration is still quite high[1] — although for organisms without color vision, this is a very minor concern.
A weakness of the vertebrate eye is the blind spot at the optic disc where the optic nerve is formed at the back of the eye; there are no light sensitive rods or cones to respond to a light stimulus at this point. By contrast, the cephalopod eye has no blind spot as the retina is in the opposite orientation.
[edit] Multiple lenses
Some marine organisms bear more than one lens; for instance the copeopod Pontella has three. The outer has a parabolic surface, countering the effects of spherical aberration while allowing a sharp image to be formed. Copilla's eyes have two lenses, which move in and out like a telescope.[1] Such arrangements are rare and poorly understood, but represent an interesting alternative construction. An interesting use of multiple lenses is seen in some hunters such as eagles and jumping spiders, which have a refractive cornea (discussed next): these have a negative lens, enlarging the observed image by up to 50% over the receptor cells, thus increasing their optical resolution.[1]
[edit] Refractive cornea
Further information: Mammalian eye
In the eyes of most terrestrial vertebrates (along with spiders and some insect larvae) the vitreous fluid has a higher refractive index than the air, relieving the lens of the function of reducing the focal length. This has freed it up for fine adjustments of focus, allowing a very high resolution to be obtained.[1] As with spherical lenses, the problem of spherical aberration caused by the lens can be countered either by using an inhomogeneous lens material, or by flattening the lens.[1] Flattening the lens has a disadvantage: the quality of vision is diminished away from the main line of focus, meaning that animals requiring all-round vision are detrimented. Such animals often display an inhomogeneous lens instead.[1]
As mentioned above, a refractive cornea is only useful out of water; in water, there is no difference in refractive index between the vitreous fluid and the surrounding water. Hence creatures which have returned to the water — penguins and seals, for example — lose their refractive cornea and return to lens-based vision. An alternative solution, borne by some divers, is to have a very strong cornea.[1]
[edit] Reflector eyes
An alternative to a lens is to line the inside of the eye with " mirrors", and reflect the image to focus at a central point.[1] The nature of these eyes means that if one were to peer into the pupil of an eye, one would see the same image that the organism would see, reflected back out.[1]
Many small organisms such as rotifers, copeopods and platyhelminths use such organs, but these are too small to produce usable images.[1] Some larger organisms, such as scallops, also use reflector eyes. The scallop Pecten has up to 100 millimeter-scale reflector eyes fringing the edge of its shell. It detects moving objects as they pass successive lenses.[1]
There is at least one vertebrate, the spookfish, whose eyes include reflective optics for focusing of light. Each of the two eyes of a spookfish collects light from both above and below; the light coming from the above is focused by a lens, while that coming from below, by a curved mirror composed of many layers of small reflective plates made of guanine crystals.[19]
[edit] Compound eyes
Portrait of a Housefly (Musca domestica)
An image of a house fly compound eye surface by using Scanning Electron Microscope at X450 magnification
Arthropods such as this carpenter bee have compound eyes
A compound eye may consist of thousands of individual photoreception units. The image perceived is a combination of inputs from the numerous ommatidia (individual "eye units"), which are located on a convex surface, thus pointing in slightly different directions. Compared with simple eyes, compound eyes possess a very large view angle, and can detect fast movement and, in some cases, the polarization of light.[20] Because the individual lenses are so small, the effects of diffraction impose a limit on the possible resolution that can be obtained. This can only be countered by increasing lens size and number — to see with a resolution comparable to our simple eyes, humans would require compound eyes which would each reach the size of their head.
Compound eyes fall into two groups: apposition eyes, which form multiple inverted images, and superposition eyes, which form a single erect image.[21] Compound eyes are common in arthropods, and are also present in annelids and some bivalved molluscs.[22]
Compound eyes, in arthropods at least, grow at their margins by the addition of new ommatidia.[23]
[edit] Apposition eyes
Apposition eyes are the most common form of eye, and are presumably the ancestral form of compound eye. They are found in all arthropod groups, although they may have evolved more than once within this phylum.[1] Some annelids and bivalves also have apposition eyes. They are also possessed by Limulus, the horseshoe crab, and there are suggestions that other chelicerates developed their simple eyes by reduction from a compound starting point.[1] (Some caterpillars appear to have evolved compound eyes from simple eyes in the opposite fashion.)
Apposition eyes work by gathering a number of images, one from each eye, and combining them in the brain, with each eye typically contributing a single point of information.
The typical apposition eye has a lens focusing light from one direction on the rhabdom, while light from other directions is absorbed by the dark wall of the ommatidium. In the other kind of apposition eye, found in the Strepsiptera, lenses are not fused to one another, and each forms an entire image; these images are combined in the brain. This is called the schizochroal compound eye or the neural superposition eye. Because images are combined additively, this arrangement allows vision under lower light levels.[1]
Structure of the ommatidia of appositon compound eyes.
[edit] Superposition eyes
The second type is named the superposition eye. The superposition eye is divided into three types; the refracting, the reflecting and the parabolic superposition eye. The refracting superposition eye has a gap between the lens and the rhabdom, and no side wall. Each lens takes light at an angle to its axis and reflects it to the same angle on the other side. The result is an image at half the radius of the eye, which is where the tips of the rhabdoms are. This kind is used mostly by nocturnal insects. In the parabolic superposition compound eye type, seen in arthropods such as mayflies, the parabolic surfaces of the inside of each facet focus light from a reflector to a sensor array. Long-bodied decapod crustaceans such as shrimp, prawns, crayfish and lobsters are alone in having reflecting superposition eyes, which also has a transparent gap but uses corner mirrors instead of lenses.
[edit] Parabolic superposition
This eye type functions by refracting light, then using a parabolic mirror to focus the image; it combines features of superposition and apposition eyes.[7]
[edit] Other
The compound eye of a dragonfly
Good fliers like flies or honey bees, or prey-catching insects like praying mantis or dragonflies, have specialized zones of ommatidia organized into a fovea area which gives acute vision. In the acute zone the eyes are flattened and the facets larger. The flattening allows more ommatidia to receive light from a spot and therefore higher resolution.
There are some exceptions from the types mentioned above. Some insects have a so-called single lens compound eye, a transitional type which is something between a superposition type of the multi-lens compound eye and the single lens eye found in animals with simple eyes. Then there is the mysid shrimp Dioptromysis paucispinosa. The shrimp has an eye of the refracting superposition type, in the rear behind this in each eye there is a single large facet that is three times in diameter the others in the eye and behind this is an enlarged crystalline cone. This projects an upright image on a specialized retina. The resulting eye is a mixture of a simple eye within a compound eye.
Another version is the pseudofaceted eye, as seen in Scutigera. This type of eye consists of a cluster of numerous ocelli on each side of the head, organized in a way that resembles a true compound eye.
The body of Ophiocoma wendtii, a type of brittle star, is covered with ommatidia, turning its whole skin into a compound eye. The same is true of many chitons.
[edit] Relationship to lifestyle
Eyes are generally adapted to the environment and lifestyle of the organism which bears them. For instance, the distribution of photoreceptors tends to match the area in which the highest acuity is required, with horizon-scanning organisms, such as those that live on the African plains, having a horizontal line of high-density ganglia, while tree-dwelling creatures which require good all-round vision tend to have a symmetrical distribution of ganglia, with acuity decreasing outwards from the centre.
Of course, for most eye types, it is impossible to diverge from a spherical form, so only the density of optical receptors can be altered. In organisms with compound eyes, it is the number of ommatidia rather than ganglia that reflects the region of highest data acquisition.[1]:23-4 Optical superposition eyes are constrained to a spherical shape, but other forms of compound eyes may deform to a shape where more ommatidia are aligned to, say, the horizon, without altering the size or density of individual ommatidia.[24] Eyes of horizon-scanning organisms have stalks so they can be easily aligned to the horizon when this is inclined, for example if the animal is on a slope.[25] An extension of this concept is that the eyes of predators typically have a zone of very acute vision at their centre, to assist in the identification of prey.[24] In deep water organisms, it may not be the centre of the eye that is enlarged. The hyperiid amphipods are deep water animals that feed on organisms above them. Their eyes are almost divided into two, with the upper region thought to be involved in detecting the silhouettes of potential prey — or predators — against the faint light of the sky above. Accordingly, deeper water hyperiids, where the light against which the silhouettes must be compared is dimmer, have larger "upper-eyes", and may lose the lower portion of their eyes altogether.[24] Depth perception can be enhanced by having eyes which are enlarged in one direction; distorting the eye slightly allows the distance to the object to be estimated with a high degree of accuracy.[7]
Acuity is higher among male organisms that mate in mid-air, as they need to be able to spot and assess potential mates against a very large backdrop.[24] On the other hand, the eyes of organisms which operate in low light levels, such as around dawn and dusk or in deep water, tend to be larger to increase the amount of light that can be captured.[24]
It is not only the shape of the eye that may be affected by lifestyle. Eyes can be the most visible parts of organisms, and this can act as a pressure on organisms to have more transparent eyes at the cost of function.[24]
Eyes may be mounted on stalks to provide better all-round vision, by lifting them above an organism's carapace; this also allows them to track predators or prey without moving the head.[7]
[edit] Acuity
A hawk's eye
Visual acuity is often measured in cycles per degree (CPD), which measures an angular resolution, or how much an eye can differentiate one object from another in terms of visual angles. Resolution in CPD can be measured by bar charts of different numbers of white — black stripe cycles. For example, if each pattern is 1.75 cm wide and is placed at 1 m distance from the eye, it will subtend an angle of 1 degree, so the number of white — black bar pairs on the pattern will be a measure of the cycles per degree of that pattern. The highest such number that the eye can resolve as stripes, or distinguish from a gray block, is then the measurement of visual acuity of the eye.
For a human eye with excellent acuity, the maximum theoretical resolution is 50 CPD[26] (1.2 arcminute per line pair, or a 0.35 mm line pair, at 1 m). A rat can resolve only about 1 to 2 CPD.[27] A horse has higher acuity through most of the visual field of its eyes than a human has, but does not match the high acuity of the human eye's central fovea region.
Spherical aberration limits the resolution of a 7 mm pupil to about 3 arcminutes per line pair. At a pupil diameter of 3 mm, the spherical aberration is greatly reduced, resulting in an improved resolution of approximately 1.7 arcminutes per line pair.[28] A resolution of 2 arcminutes per line pair, equivalent to a 1 arcminute gap in an optotype, corresponds to 20/20 (normal vision) in humans.
[edit] Color
All organisms are restricted to a small range of the electromagnetic spectrum; this varies from creature to creature, but is mainly between 400 and 700 nm[29]. This is a rather small section of the electromagnetic spectrum, probably reflecting the submarine evolution of the organ: water blocks out all but two small windows of the EM spectrum, and there has been no evolutionary pressure among land animals to broaden this range.[30]
The most sensitive pigment, rhodopsin, has a peak response at 500 nm.[31] Small changes to the genes coding for this protein can tweak the peak response by a few nm;[2] pigments in the lens can also "filter" incoming light, changing the peak response.[2] Many organisms are unable to discriminate between colors, seeing instead in shades of "grey"; colour vision necessitates a range of pigment cells which are primarily sensitive to smaller ranges of the spectrum. In primates, geckos, and other organisms, these take the form of cone cells, from which the more sensitive rod cells evolved.[31] Even if organisms are physically capable of discriminating different colours, this does not necessarily mean that they can perceive the different colours; only with behavioral tests can this be deduced.[2]
Most organisms with colour vision are able to detect ultraviolet light. This high energy light can be damaging to receptor cells. With a few exceptions (snakes, placental mammals), most organisms avoid these effects by having absorbent oil droplets around their cone cells. The alternative, developed by organisms that had lost these oil droplets in the course of evolution, is to make the lens impervious to UV light — this precludes the possibility of any UV light being detected, as it does not even reach the retina.[31]:309
[edit] Rods and cones
The retina contains two major types of light-sensitive photoreceptor cells used for vision: the rods and the cones.
Rods cannot distinguish colors, but are responsible for low-light (scotopic) monochrome (black-and-white) vision; they work well in dim light as they contain a pigment, rhodopsin (visual purple), which is sensitive at low light intensity, but saturates at higher (photopic) intensities. Rods are distributed throughout the retina but there are none at the fovea and none at the blind spot. Rod density is greater in the peripheral retina than in the central retina.
Cones are responsible for color vision. They require brighter light to function than rods require. There are three types of cones, maximally sensitive to long-wavelength, medium-wavelength, and short-wavelength light (often referred to as red, green, and blue, respectively, though the sensitivity peaks are not actually at these colors). The color seen is the combined effect of stimuli to, and responses from, these three types of cone cells. Cones are mostly concentrated in and near the fovea. Only a few are present at the sides of the retina. Objects are seen most sharply in focus when their images fall on this spot, as when one looks at an object directly. Cone cells and rods are connected through intermediate cells in the retina to nerve fibers of the optic nerve. When rods and cones are stimulated by light, the nerves send off impulses through these fibers to the brain.[31]
[edit] Pigment
The pigment molecules used in the eye are various, but can be used to define the evolutionary distance between different groups, and can also be an aid in determining which are closely related – although problems of convergence do exist.[31]
Opsins are the pigments involved in photoreception. Other pigments, such as melanin, are used to shield the photoreceptor cells from light leaking in from the sides. The opsin protein group evolved long before the last common ancestor of animals, and has continued to diversify since.[2]
There are two types of opsin involved in vision; c-opsins, which are associated with ciliary-type photoreceptor cells, and r-opsins, associated with rhabdomeric photoreceptor cells.[32] The eyes of vertebrates usually contain cilliary cells with c-opsins, and (bilaterian) invertebrates have rhabdomeric cells in the eye with r-opsins. However, some ganglion cells of vertebrates express r-opsins, suggesting that their ancestors used this pigment in vision, and that remnants survive in the eyes.[32] Likewise, c-opsins have been found to be expressed in the brain of some invertebrates. They may have been expressed in ciliary cells of larval eyes, which were subsequently resorbed into the brain on metamorphosis to the adult form.[32] C-opsins are also found in some derived bilaterian-invertebrate eyes, such as the pallial eyes of the bivalve molluscs; however, the lateral eyes (which were presumably the ancestral type for this group, if eyes evolved once there) always use r-opsins.[32] Cnidaria, which are an outgroup to the taxa mentioned above, express c-opsins - but r-opsins are yet to be found in this group.[32] Incidentally, the melanin produced in the cnidaria is produced in the same fashion as that in vertebrates, suggesting the common descent of this pigment.[32]
[edit]
The simplest "eyes", such as those in unicellular organisms, do nothing but detect whether the surroundings are light or dark, which is sufficient for the entrainment of circadian rhythms. From more complex eyes, retinal photosensitive ganglion cells send signals along the retinohypothalamic tract to the suprachiasmatic nuclei to effect circadian adjustment.
Complex eyes can distinguish shapes and colors. The visual fields of many organisms, especially predators, involve large areas of binocular vision to improve depth perception; in other organisms, eyes are located so as to maximise the field of view, such as in rabbits and horses, which have monocular vision.
The first proto-eyes evolved among animals 540 million years ago, about the time of the Cambrian explosion.[citation needed] The last common ancestor of animals possessed the biochemical toolkit necessary for vision, and more advanced eyes have evolved in 96% of animal species in 6 of the thirty-plus[note 1] main phyla.[1] In most vertebrates and some molluscs, the eye works by allowing light to enter it and project onto a light-sensitive panel of cells, known as the retina, at the rear of the eye. The cone cells (for color) and the rod cells (for low-light contrasts) in the retina detect and convert light into neural signals for vision. The visual signals are then transmitted to the brain via the optic nerve. Such eyes are typically roughly spherical, filled with a transparent gel-like substance called the vitreous humour, with a focusing lens and often an iris; the relaxing or tightening of the muscles around the iris change the size of the pupil, thereby regulating the amount of light that enters the eye,[3] and reducing aberrations when there is enough light.[4]
The eyes of cephalopods, fish, amphibians and snakes usually have fixed lens shapes, and focusing vision is achieved by telescoping the lens — similar to how a camera focuses.[5]
Compound eyes are found among the arthropods and are composed of many simple facets which, depending on the details of anatomy, may give either a single pixelated image or multiple images, per eye. Each sensor has its own lens and photosensitive cell(s). Some eyes have up to 28,000 such sensors, which are arranged hexagonally, and which can give a full 360-degree field of vision. Compound eyes are very sensitive to motion. Some arthropods, including many Strepsiptera, have compound eyes of only a few facets, each with a retina capable of creating an image, creating vision. With each eye viewing a different thing, a fused image from all the eyes is produced in the brain, providing very different, high-resolution images.
Possessing detailed hyperspectral color vision, the Mantis shrimp has been reported to have the world's most complex color vision system.[6] Trilobites, which are now extinct, had unique compound eyes. They used clear calcite crystals to form the lenses of their eyes. In this, they differ from most other arthropods, which have soft eyes. The number of lenses in such an eye varied, however: some trilobites had only one, and some had thousands of lenses in one eye.
In contrast to compound eyes, simple eyes are those that have a single lens. For example, jumping spiders have a large pair of simple eyes with a narrow field of view, supported by an array of other, smaller eyes for peripheral vision. Some insect larvae, like caterpillars, have a different type of simple eye (stemmata) which gives a rough image. Some of the simplest eyes, called ocelli, can be found in animals like some of the snails, which cannot actually "see" in the normal sense. They do have photosensitive cells, but no lens and no other means of projecting an image onto these cells. They can distinguish between light and dark, but no more. This enables snails to keep out of direct sunlight. In organisms dwelling near deep-sea vents, compound eyes have been secondarily simplified and adapted to spot the infra-red light produced by the hot vents - in this way the bearers can spot hot springs and avoid being boiled alive.[7]
[edit] Evolution
Main article: Evolution of the eye
Diagram of eye evolution.svg
The common origin (monophyly) of all animal eyes is now widely accepted as fact based on shared anatomical and genetic features of all eyes; that is, all modern eyes, varied as they are, have their origins in a proto-eye believed to have evolved some 540 million years ago.[8][9][10] The majority of the advancements in early eyes are believed to have taken only a few million years to develop, as the first predator to gain true imaging would have touched off an "arms race".[11] Prey animals and competing predators alike would be forced to rapidly match or exceed any such capabilities to survive. Hence multiple eye types and subtypes developed in parallel.
Eyes in various animals show adaption to their requirements. For example, birds of prey have much greater visual acuity than humans, and some can see ultraviolet light. The different forms of eye in, for example, vertebrates and mollusks are often cited as examples of parallel evolution, despite their distant common ancestry.
The earliest eyes, called "eyespots", were simple patches of photoreceptor cells, physically similar to the receptor patches for taste and smell. These eyespots could only sense ambient brightness: they could distinguish light and dark, but not the direction of the lightsource.[12] This gradually changed as the eyespot depressed into a shallow "cup" shape, granting the ability to slightly discriminate directional brightness by using the angle at which the light hit certain cells to identify the source. The pit deepened over time, the opening diminished in size, and the number of photoreceptor cells increased, forming an effective pinhole camera that was capable of slightly distinguishing dim shapes.[13]
The thin overgrowth of transparent cells over the eye's aperture, originally formed to prevent damage to the eyespot, allowed the segregated contents of the eye chamber to specialize into a transparent humour that optimized colour filtering, blocked harmful radiation, improved the eye's refractive index, and allowed functionality outside of water. The transparent protective cells eventually split into two layers, with circulatory fluid in between that allowed wider viewing angles and greater imaging resolution, and the thickness of the transparent layer gradually increased, in most species with the transparent crystallin protein.[14]
The gap between tissue layers naturally formed a bioconvex shape, an optimally ideal structure for a normal refractive index. Independently, a transparent layer and a nontransparent layer split forward from the lens: the cornea and iris. Separation of the forward layer again forms a humour, the aqueous humour. This increases refractive power and again eases circulatory problems. Formation of a nontransparent ring allows more blood vessels, more circulation, and larger eye sizes.[14]
[edit] Types of eye
Nature has produced ten different eye layouts — indeed every way of capturing an image has evolved at least once in nature, with the exceptions of zoom and Fresnel lenses. Eye types can be categorized into "simple eyes", with one concave chamber, and "compound eyes", which comprise a number of individual lenses laid out on a convex surface.[1] Note that "simple" does not imply a reduced level of complexity or acuity. Indeed, any eye type can be adapted for almost any behaviour or environment. The only limitations specific to eye types are that of resolution — the physics of compound eyes prevents them from achieving a resolution better than 1°. Also, superposition eyes can achieve greater sensitivity than apposition eyes, so are better suited to dark-dwelling creatures.[1] Eyes also fall into two groups on the basis of their photoreceptor's cellular construction, with the photoreceptor cells either being cilliated (as in the vertebrates) or rhabdomic. These two groups are not monophyletic; the cnidaira also possess cilliated cells, [15] and some annelids possess both.[16]
[edit] Simple eyes
Simple eyes are rather ubiquitous, and lens-bearing eyes have evolved at least seven times; in vertebrates, cephalopods, annelids, crustacea and cubozoa.[17]
[edit] Pit eyes
Pit eyes, also known as stemma, are eye-spots which may be set into a pit to reduce the angles of light that enters and affects the eyespot, to allow the organism to deduce the angle of incoming light.[1] Found in about 85% of phyla, these basic forms were probably the precursors to more advanced types of "simple eye". They are small, comprising up to about 100 cells covering about 100 µm.[1] The directionality can be improved by reducing the size of the aperture, by incorporating a reflective layer behind the receptor cells, or by filling the pit with a refractile material.[1]
[edit] Pinhole eye
Nautiluses bear a pinhole eye
The pinhole eye is an "advanced" form of pit eye incorporating several improvements, most notably a small aperture (which may be adjustable) and deep pit. It is only found in the nautiloids.[1] Without a lens to focus the image, it produces a blurry image, and will blur out a point to the size of the aperture. Consequently, nautiloids can't discriminate between objects with an angular separation of less than 11°.[1] Shrinking the aperture would produce a sharper image, but let in less light.[1]
[edit] Spherical lensed eye
The resolution of pit eyes can be greatly improved by incorporating a material with a higher refractive index to form a lens, which may greatly reduce the blur radius encountered — hence increasing the resolution obtainable.[1] The most basic form, still seen in some gastropods and annelids, consists of a lens of one refractive index. A far sharper image can be obtained using materials with a high refractive index, decreasing to the edges — this decreases the focal length and thus allows a sharp image to form on the retina.[1] This also allows a larger aperture for a given sharpness of image, allowing more light to enter the lens; and a flatter lens, reducing spherical aberration.[1] Such an inhomogeneous lens is necessary in order for the focal length to drop from about 4 times the lens radius, to 2.5 radii.[1]
Heterogeneous eyes have evolved at least eight times — four or more times in gastropods, once in the copepods, once in the annelids and once in the cephalopods.[1] No aquatic organisms possess homogeneous lenses; presumably the evolutionary pressure for a heterogeneous lens is great enough for this stage to be quickly "outgrown".[1]
This eye creates an image that is sharp enough that motion of the eye can cause significant blurring. To minimize the effect of eye motion while the animal moves, most such eyes have stabilizing eye muscles.[1]
The ocelli of insects bear a simple lens, but their focal point always lies behind the retina; consequently they can never form a sharp image. This capitulates the function of the eye. Ocelli (pit-type eyes of arthropods) blur the image across the whole retina, and are consequently excellent at responding to rapid changes in light intensity across the whole visual field — this fast response is further accelerated by the large nerve bundles which rush the information to the brain.[18] Focusing the image would also cause the sun's image to be focused on a few receptors, with the possibility of damage under the intense light; shielding the receptors would block out some light and thus reduce their sensitivity.[18] This fast response has led to suggestions that the ocelli of insects are used mainly in flight, because they can be used to detect sudden changes in which way is up (because light, especially UV light which is absorbed by vegetation, usually comes from above).[18]
[edit] Weaknesses
One weakness of this eye construction is that chromatic aberration is still quite high[1] — although for organisms without color vision, this is a very minor concern.
A weakness of the vertebrate eye is the blind spot at the optic disc where the optic nerve is formed at the back of the eye; there are no light sensitive rods or cones to respond to a light stimulus at this point. By contrast, the cephalopod eye has no blind spot as the retina is in the opposite orientation.
[edit] Multiple lenses
Some marine organisms bear more than one lens; for instance the copeopod Pontella has three. The outer has a parabolic surface, countering the effects of spherical aberration while allowing a sharp image to be formed. Copilla's eyes have two lenses, which move in and out like a telescope.[1] Such arrangements are rare and poorly understood, but represent an interesting alternative construction. An interesting use of multiple lenses is seen in some hunters such as eagles and jumping spiders, which have a refractive cornea (discussed next): these have a negative lens, enlarging the observed image by up to 50% over the receptor cells, thus increasing their optical resolution.[1]
[edit] Refractive cornea
Further information: Mammalian eye
In the eyes of most terrestrial vertebrates (along with spiders and some insect larvae) the vitreous fluid has a higher refractive index than the air, relieving the lens of the function of reducing the focal length. This has freed it up for fine adjustments of focus, allowing a very high resolution to be obtained.[1] As with spherical lenses, the problem of spherical aberration caused by the lens can be countered either by using an inhomogeneous lens material, or by flattening the lens.[1] Flattening the lens has a disadvantage: the quality of vision is diminished away from the main line of focus, meaning that animals requiring all-round vision are detrimented. Such animals often display an inhomogeneous lens instead.[1]
As mentioned above, a refractive cornea is only useful out of water; in water, there is no difference in refractive index between the vitreous fluid and the surrounding water. Hence creatures which have returned to the water — penguins and seals, for example — lose their refractive cornea and return to lens-based vision. An alternative solution, borne by some divers, is to have a very strong cornea.[1]
[edit] Reflector eyes
An alternative to a lens is to line the inside of the eye with " mirrors", and reflect the image to focus at a central point.[1] The nature of these eyes means that if one were to peer into the pupil of an eye, one would see the same image that the organism would see, reflected back out.[1]
Many small organisms such as rotifers, copeopods and platyhelminths use such organs, but these are too small to produce usable images.[1] Some larger organisms, such as scallops, also use reflector eyes. The scallop Pecten has up to 100 millimeter-scale reflector eyes fringing the edge of its shell. It detects moving objects as they pass successive lenses.[1]
There is at least one vertebrate, the spookfish, whose eyes include reflective optics for focusing of light. Each of the two eyes of a spookfish collects light from both above and below; the light coming from the above is focused by a lens, while that coming from below, by a curved mirror composed of many layers of small reflective plates made of guanine crystals.[19]
[edit] Compound eyes
Portrait of a Housefly (Musca domestica)
An image of a house fly compound eye surface by using Scanning Electron Microscope at X450 magnification
Arthropods such as this carpenter bee have compound eyes
A compound eye may consist of thousands of individual photoreception units. The image perceived is a combination of inputs from the numerous ommatidia (individual "eye units"), which are located on a convex surface, thus pointing in slightly different directions. Compared with simple eyes, compound eyes possess a very large view angle, and can detect fast movement and, in some cases, the polarization of light.[20] Because the individual lenses are so small, the effects of diffraction impose a limit on the possible resolution that can be obtained. This can only be countered by increasing lens size and number — to see with a resolution comparable to our simple eyes, humans would require compound eyes which would each reach the size of their head.
Compound eyes fall into two groups: apposition eyes, which form multiple inverted images, and superposition eyes, which form a single erect image.[21] Compound eyes are common in arthropods, and are also present in annelids and some bivalved molluscs.[22]
Compound eyes, in arthropods at least, grow at their margins by the addition of new ommatidia.[23]
[edit] Apposition eyes
Apposition eyes are the most common form of eye, and are presumably the ancestral form of compound eye. They are found in all arthropod groups, although they may have evolved more than once within this phylum.[1] Some annelids and bivalves also have apposition eyes. They are also possessed by Limulus, the horseshoe crab, and there are suggestions that other chelicerates developed their simple eyes by reduction from a compound starting point.[1] (Some caterpillars appear to have evolved compound eyes from simple eyes in the opposite fashion.)
Apposition eyes work by gathering a number of images, one from each eye, and combining them in the brain, with each eye typically contributing a single point of information.
The typical apposition eye has a lens focusing light from one direction on the rhabdom, while light from other directions is absorbed by the dark wall of the ommatidium. In the other kind of apposition eye, found in the Strepsiptera, lenses are not fused to one another, and each forms an entire image; these images are combined in the brain. This is called the schizochroal compound eye or the neural superposition eye. Because images are combined additively, this arrangement allows vision under lower light levels.[1]
Structure of the ommatidia of appositon compound eyes.
[edit] Superposition eyes
The second type is named the superposition eye. The superposition eye is divided into three types; the refracting, the reflecting and the parabolic superposition eye. The refracting superposition eye has a gap between the lens and the rhabdom, and no side wall. Each lens takes light at an angle to its axis and reflects it to the same angle on the other side. The result is an image at half the radius of the eye, which is where the tips of the rhabdoms are. This kind is used mostly by nocturnal insects. In the parabolic superposition compound eye type, seen in arthropods such as mayflies, the parabolic surfaces of the inside of each facet focus light from a reflector to a sensor array. Long-bodied decapod crustaceans such as shrimp, prawns, crayfish and lobsters are alone in having reflecting superposition eyes, which also has a transparent gap but uses corner mirrors instead of lenses.
[edit] Parabolic superposition
This eye type functions by refracting light, then using a parabolic mirror to focus the image; it combines features of superposition and apposition eyes.[7]
[edit] Other
The compound eye of a dragonfly
Good fliers like flies or honey bees, or prey-catching insects like praying mantis or dragonflies, have specialized zones of ommatidia organized into a fovea area which gives acute vision. In the acute zone the eyes are flattened and the facets larger. The flattening allows more ommatidia to receive light from a spot and therefore higher resolution.
There are some exceptions from the types mentioned above. Some insects have a so-called single lens compound eye, a transitional type which is something between a superposition type of the multi-lens compound eye and the single lens eye found in animals with simple eyes. Then there is the mysid shrimp Dioptromysis paucispinosa. The shrimp has an eye of the refracting superposition type, in the rear behind this in each eye there is a single large facet that is three times in diameter the others in the eye and behind this is an enlarged crystalline cone. This projects an upright image on a specialized retina. The resulting eye is a mixture of a simple eye within a compound eye.
Another version is the pseudofaceted eye, as seen in Scutigera. This type of eye consists of a cluster of numerous ocelli on each side of the head, organized in a way that resembles a true compound eye.
The body of Ophiocoma wendtii, a type of brittle star, is covered with ommatidia, turning its whole skin into a compound eye. The same is true of many chitons.
[edit] Relationship to lifestyle
Eyes are generally adapted to the environment and lifestyle of the organism which bears them. For instance, the distribution of photoreceptors tends to match the area in which the highest acuity is required, with horizon-scanning organisms, such as those that live on the African plains, having a horizontal line of high-density ganglia, while tree-dwelling creatures which require good all-round vision tend to have a symmetrical distribution of ganglia, with acuity decreasing outwards from the centre.
Of course, for most eye types, it is impossible to diverge from a spherical form, so only the density of optical receptors can be altered. In organisms with compound eyes, it is the number of ommatidia rather than ganglia that reflects the region of highest data acquisition.[1]:23-4 Optical superposition eyes are constrained to a spherical shape, but other forms of compound eyes may deform to a shape where more ommatidia are aligned to, say, the horizon, without altering the size or density of individual ommatidia.[24] Eyes of horizon-scanning organisms have stalks so they can be easily aligned to the horizon when this is inclined, for example if the animal is on a slope.[25] An extension of this concept is that the eyes of predators typically have a zone of very acute vision at their centre, to assist in the identification of prey.[24] In deep water organisms, it may not be the centre of the eye that is enlarged. The hyperiid amphipods are deep water animals that feed on organisms above them. Their eyes are almost divided into two, with the upper region thought to be involved in detecting the silhouettes of potential prey — or predators — against the faint light of the sky above. Accordingly, deeper water hyperiids, where the light against which the silhouettes must be compared is dimmer, have larger "upper-eyes", and may lose the lower portion of their eyes altogether.[24] Depth perception can be enhanced by having eyes which are enlarged in one direction; distorting the eye slightly allows the distance to the object to be estimated with a high degree of accuracy.[7]
Acuity is higher among male organisms that mate in mid-air, as they need to be able to spot and assess potential mates against a very large backdrop.[24] On the other hand, the eyes of organisms which operate in low light levels, such as around dawn and dusk or in deep water, tend to be larger to increase the amount of light that can be captured.[24]
It is not only the shape of the eye that may be affected by lifestyle. Eyes can be the most visible parts of organisms, and this can act as a pressure on organisms to have more transparent eyes at the cost of function.[24]
Eyes may be mounted on stalks to provide better all-round vision, by lifting them above an organism's carapace; this also allows them to track predators or prey without moving the head.[7]
[edit] Acuity
A hawk's eye
Visual acuity is often measured in cycles per degree (CPD), which measures an angular resolution, or how much an eye can differentiate one object from another in terms of visual angles. Resolution in CPD can be measured by bar charts of different numbers of white — black stripe cycles. For example, if each pattern is 1.75 cm wide and is placed at 1 m distance from the eye, it will subtend an angle of 1 degree, so the number of white — black bar pairs on the pattern will be a measure of the cycles per degree of that pattern. The highest such number that the eye can resolve as stripes, or distinguish from a gray block, is then the measurement of visual acuity of the eye.
For a human eye with excellent acuity, the maximum theoretical resolution is 50 CPD[26] (1.2 arcminute per line pair, or a 0.35 mm line pair, at 1 m). A rat can resolve only about 1 to 2 CPD.[27] A horse has higher acuity through most of the visual field of its eyes than a human has, but does not match the high acuity of the human eye's central fovea region.
Spherical aberration limits the resolution of a 7 mm pupil to about 3 arcminutes per line pair. At a pupil diameter of 3 mm, the spherical aberration is greatly reduced, resulting in an improved resolution of approximately 1.7 arcminutes per line pair.[28] A resolution of 2 arcminutes per line pair, equivalent to a 1 arcminute gap in an optotype, corresponds to 20/20 (normal vision) in humans.
[edit] Color
All organisms are restricted to a small range of the electromagnetic spectrum; this varies from creature to creature, but is mainly between 400 and 700 nm[29]. This is a rather small section of the electromagnetic spectrum, probably reflecting the submarine evolution of the organ: water blocks out all but two small windows of the EM spectrum, and there has been no evolutionary pressure among land animals to broaden this range.[30]
The most sensitive pigment, rhodopsin, has a peak response at 500 nm.[31] Small changes to the genes coding for this protein can tweak the peak response by a few nm;[2] pigments in the lens can also "filter" incoming light, changing the peak response.[2] Many organisms are unable to discriminate between colors, seeing instead in shades of "grey"; colour vision necessitates a range of pigment cells which are primarily sensitive to smaller ranges of the spectrum. In primates, geckos, and other organisms, these take the form of cone cells, from which the more sensitive rod cells evolved.[31] Even if organisms are physically capable of discriminating different colours, this does not necessarily mean that they can perceive the different colours; only with behavioral tests can this be deduced.[2]
Most organisms with colour vision are able to detect ultraviolet light. This high energy light can be damaging to receptor cells. With a few exceptions (snakes, placental mammals), most organisms avoid these effects by having absorbent oil droplets around their cone cells. The alternative, developed by organisms that had lost these oil droplets in the course of evolution, is to make the lens impervious to UV light — this precludes the possibility of any UV light being detected, as it does not even reach the retina.[31]:309
[edit] Rods and cones
The retina contains two major types of light-sensitive photoreceptor cells used for vision: the rods and the cones.
Rods cannot distinguish colors, but are responsible for low-light (scotopic) monochrome (black-and-white) vision; they work well in dim light as they contain a pigment, rhodopsin (visual purple), which is sensitive at low light intensity, but saturates at higher (photopic) intensities. Rods are distributed throughout the retina but there are none at the fovea and none at the blind spot. Rod density is greater in the peripheral retina than in the central retina.
Cones are responsible for color vision. They require brighter light to function than rods require. There are three types of cones, maximally sensitive to long-wavelength, medium-wavelength, and short-wavelength light (often referred to as red, green, and blue, respectively, though the sensitivity peaks are not actually at these colors). The color seen is the combined effect of stimuli to, and responses from, these three types of cone cells. Cones are mostly concentrated in and near the fovea. Only a few are present at the sides of the retina. Objects are seen most sharply in focus when their images fall on this spot, as when one looks at an object directly. Cone cells and rods are connected through intermediate cells in the retina to nerve fibers of the optic nerve. When rods and cones are stimulated by light, the nerves send off impulses through these fibers to the brain.[31]
[edit] Pigment
The pigment molecules used in the eye are various, but can be used to define the evolutionary distance between different groups, and can also be an aid in determining which are closely related – although problems of convergence do exist.[31]
Opsins are the pigments involved in photoreception. Other pigments, such as melanin, are used to shield the photoreceptor cells from light leaking in from the sides. The opsin protein group evolved long before the last common ancestor of animals, and has continued to diversify since.[2]
There are two types of opsin involved in vision; c-opsins, which are associated with ciliary-type photoreceptor cells, and r-opsins, associated with rhabdomeric photoreceptor cells.[32] The eyes of vertebrates usually contain cilliary cells with c-opsins, and (bilaterian) invertebrates have rhabdomeric cells in the eye with r-opsins. However, some ganglion cells of vertebrates express r-opsins, suggesting that their ancestors used this pigment in vision, and that remnants survive in the eyes.[32] Likewise, c-opsins have been found to be expressed in the brain of some invertebrates. They may have been expressed in ciliary cells of larval eyes, which were subsequently resorbed into the brain on metamorphosis to the adult form.[32] C-opsins are also found in some derived bilaterian-invertebrate eyes, such as the pallial eyes of the bivalve molluscs; however, the lateral eyes (which were presumably the ancestral type for this group, if eyes evolved once there) always use r-opsins.[32] Cnidaria, which are an outgroup to the taxa mentioned above, express c-opsins - but r-opsins are yet to be found in this group.[32] Incidentally, the melanin produced in the cnidaria is produced in the same fashion as that in vertebrates, suggesting the common descent of this pigment.[32]
[edit]
Associations, Societies, Foundations for Eye Health
-A-
AAOSE
American Association for Ophthalmic Standardized Echography
AAPOS Home Page
American Association for Pediatric Ophthalmology and Strabismus. A resource for Pediatric Ophthalmologists, Strabismologists, related personnel and patients.
Alabama Academy of Ophthalmology
ALAO website is a trade association made up of ophthalmologists who are licensed and practicing in the state of Alabama,and Corporate representatives who provide goods or services of value to ophthalmologists .
Alaska Optometric Physicians Association
News, meetings,web links, and directory search of optometrists.
Alaska State Ophthalmological Society
does not have a website as of April 2006.
Alberta Association of Optometrists
Website for professional optometrists in Alberta, Canada. It includes eyecare information.
All India Ophthalmological Society
Conference abstracts, CME, Full text journal articles, membership directory, newsletter and more. (may be slow to load).
AMD Alliance International
A global coalition of vision and seniors' organizations dedicated to the raising awareness of AMD and the options available for prevention, early detection, treatment, rehabilitation and support services.
AMDF: American Macular Degeneration Foundation
American Academy of Ophthalmology
This site serves the professional needs of the Academy's members.
American Academy of Optometry
About membership services, the Annual Meeting, News, additional links.
American Academy of Optometry, British Chapter
Tutorials and pages upon pages of Information for, by or about Optometrists and Optometry.
American Academy of Pediatrics. Section on Ophthalmology
Provides an educational forum for the discussion of problems and treatments related to ophthalmology in children. Includes pdf files of published policy statements.
American Association for Pediatric Ophthalmology and Strabismus
American Association for Pediatric Ophthalmology and Strabismus. A resource for Pediatric Ophthalmologists, Strabismologists, related personnel and patients.
American Association of Ophthalmic Pathologists
A professional association of medical doctors who practice, teach and or engage in research in ophthalmic pathology.
American Board of Ophthalmology
History of the Board, Mission and intent, Examination Statistics, Applications, Requirements, Dates and Deadlines, Requirements for Recertification. Links to the American Board of Medical Specialties.
American College of Veterinary Ophthalmologists
ACVO is the association that establishes criteria for certifying veterinary ophthalmologists. Site contains profiles of diplomates, areas for professionals and for the public, a calendar of events, news items and related links.
American Foundation for the Blind
Information about the organization, its services and publications. Includes the AFB Directory of Services for Blind and Visually Impaired Persons in the United States and Canada. Locate organizations in the United States and Canada that provide services to people who are blind or visually impaired and their families. The Services Center is based on the AFB Directory of Services for Blind and Visually Impaired Persons in the United States and Canada. You can use the Services Center to find a service provider by name, state, country, or service category.
American Glaucoma Sociey
Promotes excellence in the care of patients with glaucoma and preserves or enhances vision by supporting glaucoma specialists and scientists through the advancement of education and research. Has physician and patient resource centers.
American Nystagmus Network
Information about Nystagmus, links to a discussion group, ANN conferences. The Site Map is helpful in navigating the site.
American Ophthalmological Society
Promotes excellence in patient care, education and research, to address essential issues in medicine, and to advance the art and science of ophthalmology. Transactions are available online.
American Optometric Association
About the AOA. Common eye conditions and diseases, children's vision, contact lens information, sports & vision, eyecare tips, an educations center (for kids, for teachers and for people considering optometry as a career). Recent press releases
American Optometric Foundation
The foundation for the American Academy of Optometry.
American Osteopathic College of Ophthalmology
Profesional site for Osteopathic ophthalmologists. Includes directory of members and FAQ for patients.
American Public Health Association, Vision Care Section
The VCS serves as an advocate to ensure equality in, and access to, vision and eye health care, and to ensure inclusion of vision in public health policy. Websiter contains information about the organization and resolutions, a list of officers and upcoming events.
American Retina Foundation
For patient education about retinal problems. Supported by Alcon grant. Physicans search service.
American Society of Ocularists
The American Society of Ocularists is an international, non-profit, professional and educational organization founded in 1957 by technicians specializing in the fabricating and fitting of custom-made ocular prosthetics (artificial eyes).
American Society of Cataract & Refractive Surgery
Members have access to images. Surgeon search service. Has meeting and government relations sections.
American Society of Ophthalmic Plastic & Reconstructive Surgery: ASOPRS
Membership directory, Information about ophthalmic plastic and reconstructive surgery: eyelid, orbit, eye, lacrimal, cosmetic surgery, oculoplastics, prosthesis, trauma, blepharoplasty, blepharospasm, thyroid eye disease, laser, facial surgery, fractures, congenital deformities, fellowship information. The site index is very helpful
American Society of Ocularists
An international, non-profit, professional and educational organization founded in 1957 by professionals specializing in the fabricating and fitting of custom-made ocular prosthetics (artificial eyes). Has a search engine to locate ocularists. FAQ's listed under Resources.
American Society of Ophthalmic Administrators
The ASOA is a membership organization focusing on the business of ophthalmology. They publish Administrative Eye Care and offer Certification of Ophthalmic Executives. They offer online courses in administration.
American Society of Retina Specialists
Information about the society, its meetings and publications (including the online journal). Listserver information (for members). Disease Information (Information about Age-Related Macular Degeneration. Physicians search service.
American Society of Veterinary Ophthalmologists
American Uveitis Society
Resource for individuals with an interest in inflammatory eye diseases, including patients, families, researchers, ophthalmologists and other healthcare providers.
Aravind Eye Care System
WHO collaborating centre for prevention of blindness located in Madurai, Theni, Tirunelveli Coimbatore, and Pondicherry, India. See the Aravind Eyesite, an online collection of comprehensive resources for eye care programs around the world. It shares tools that help plan, implement, manage and assess high quality, efficient, and sustainable eye care programs in the developing world.
Arizona Ophthalmological Society
Serves as a source of educational, social, and ethical exchange for the member Eye MDs of the State of Arizona. Has a member's directory.
Arizona Optometric Association
Search of AZ optometrists, Some patient education and professional opportunities.
Arkansas Ophthalmological Society
Promotes and advances the science and art of medical eye care. Has information for public and ophthalmologists.
Armed Forces Optometric Society
Lists officers and mission statement. Has some web links.
ARVO
The Association for Research in Vision and Ophthalmology (ARVO).
ASCRS - ASOA
American Society of Cataract and Refractive Surgery. Site of EyeWorld news service.
ASOPRS: see American Society of Ophthalmic Plastic & Reconstructive Surgery
ASORN
American Society of Ophthalmic Registered Nurses. Information about the organization and its publications, services and products, Information about Certification.
ASRS: see American Society of Retina Specialists
Association for Macular Diseases, Inc.
About the association, a monthly newsletter and more.
Association des optométristes du Québec
Web site in French. Sections for general public and optometrists.
Association for Ocular Pharmacology and Therapeutics
Hosts biennial meetings. For vision scientists interested in the exchange of information about ocular pharmacology. Publishes the Journal of Ocular Pharmacology and Therapeutics.
Association of Optometric Contact Lens Educators
The Association of Optometric Contact Lens Educators is committed to fostering the highest levels of education in the areas of cornea and contact lenses and supporting the faculty in these areas at each of the North American schools and colleges of optometry..
Association of Optometrists (London, England)
Promotes the professional and clinical independence of its members and the profession .
Association of Regulatory Boards of Optometry
The Association of Regulatory Boards of Optometry (ARBO) is the federation of state, provincial, and territorial boards of optometry throughout North America. Boards of optometry serve as the licensing and regulatory arm of the optometric profession by formulating rules, or regulations, that govern and enforce the laws that grant the privilege to practice optometry, which are enacted by state legislatures.
Association of Schools and Colleges of Optometry
ASCO's website lists Accredited Schools and College of Optometry, residency sites, optometric faculty directory, FAQ about optometry and links to related sites.
Association of Technical Personnel in Ophthalmology
Association of University Professors of Ophthalmology
Represents academic departments of ophthalmology with open positions and a newsletter.
Association of Veterans Affairs Ophthalmologists
Has a membership listing and pdf copies of newsletters.
Association of Vision Science Librarians (AVSL)
The Association of Vision Science Librarians is an international organization composed of professional librarians, or persons acting in that capacity, whose collections and services include the literature of vision. Among current members are individuals who work within libraries that serve educational institutions, eye clinics and hospitals, and private companies with an interest in eye or vision-related products and services. The Association is a Special Interest Group of both the Association of Schools and Colleges of Optometry and the Medical Library Association. Site includes: Publications: Standards, Guidelines, Union List of Vision-Related Serials, Opening Day Book Collection, Core List Audio-Visual Collection, Publication Considerations in the Age of Electronic Opportunities. Includes links to a Subject Guide to Internet Resources in Vision Science, a list of Spanish Language Books, E-Books & Journals, CD-ROM Titles in Vision Science, Directories & Statistical Sources, Eye Care Statistics, and Library Catalogs.
AVSL: see Association of Vision Science Librarians
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Belgian Society of Ophthalmology
Multi-lingual site with information about the organization, its publications, congresses, and links to other sites. It has an extensive calendar of ophthalmology events and congresses that is well worth the visit.
Beta Sigma Kappa
International Optometric Honor Society
Brazilian Society of Laser and Ophthalmic Surgery
Alternative name: Brazilian Laser Ophthalmological Surgery Society. An official society of the Brazilian Council of Ophthalmology. (may be slow to load)
British Columbia Association of Optometrists
The voice of Optometrists across the province;it is prominently affiliated with provincial, national and government organizations
British Computer Association of the Blind
British Contact Lens Association
About the association. Clinical Conference announcements, continuing education sourses and scientific meetings.
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California Academy of Ophthalmology
Serves the total visual health care needs of the people through public and professional education, membership services, and legislative advocacy. It is dedicated to the public's direct access to an ophthalmologist's care.
California Optometric Association
For CA professionals. Includes calendar of events.
Canadian Association of Optometrists
CAO is the professional association that represents Doctors of Optometry in Canada. It is also the national federation of ten provincial associations of optometrists and represents over 3,200 members across Canada. This site is committed to providing quality information about Optometry, the national association, and vision and eye health.
Canadian Examiners in Optometry (CEO)
Canadian Examiners in Optometry (CEO) is a not-for-profit corporation whose shareholders are the ten provincial Regulators. CEO was created by the Regulators to address matters of common interest. These include 1)describing the profession as practised in Canada, including describing quality practice, 2)assessing the competence of individual optometrists in the practice of optometry and providing the assessment results to the individuals and to relevant regulators, 3)providing mechanisms to evaluate the quality of practice of optometrists in Canada.
Canadian Ophthalmological Society (COS)
(Eyesite.ca) About the society, its programs, services and affiliations as well as a calendar of events, and information for the public.
The Canadian Orthoptic Society (TCOS)
CareerMD
Current information on practice opportunities in Ophthalmology and Ophthalmology Subspecialties (and other specialties). Listings have been submitted by employers who are interested in reaching current Ophthalmology residents and fellows. Each posting includes a brief description of the opportunity, as well as contact information for all inquiries.
Center for the Partially Sighted
Promotes independent living for people of all ages with impaired sight.
College of Optometrists (London, England)
The College of Optometrists is the Professional, Scientific and Examining Body for Optometry in the UK working for the public benefit.
College of Optometrists in Vision Development
St. Louis, Missouri. This site includes a library of articles about many vision conditions and treatments, also information about the organization and links to other sites.
Colorado Society of Eye Physicians and Surgeons
An organization for Colorado ophthalmologists. Sponsors CE and advocates legislative actions.
Commission on Opticianry Accreditation
COA is the organization recognized by the U.S. Department of Education to accredit Opticianry training in the United States.
Connecticut Society of Eye Physicians and Surgeons
Represents more than 300 ophthalmologists in the State of Connecticut - and their patients. It has programs for education and advocacy.
Contact Lens Association of Ophthalmologists
CLAO's mission is to advance quality medical eye care for the public by providing comprehensive ophthalmologists and other eye care professionals with education and training in contact lenses and related eye care science.
Contact Lens Council
Glossary, Contact Lens History, Contact Lens FAQ, Health and Safety.
Contact Lens Society of America
Has a member search engine. Sponsors an annual meeting and CE courses. It is dedicated to the education, evolution, and promotion of contact lens technology.
Cornea Society
Information for professionals.
Council for Refractive Surgery Quality Assurance
CRSQA is a nonprofit consumer/patient health organization that certifies surgeons who perform eye surgery to eliminate glasses. Extensive information regarding refractive surgery. Links to certified surgeons and other vision related websites.
Council on Optometric Practitioner Education (COPE)
COPE is a committee of the Association of Regulatory Boards of Optometry (ARBO), which is the association that currently represents 50 US optometry boards, 4 US territories/jurisdictions, and 2 Canadian boards. Its mission is to: 1)coordinate the review and approval of continuing optometric education courses on behalf of state boards on a national basis; 2)reduce duplication of effort by state boards; 3)create a uniform method of recording continuing education courses on a national basis; 4)be the clearinghouse for information about continuing education programs and courses utilized by licensed optometrists to fulfill their continuing education requirements for license renewal; and 5) encourage program sponsors to offer high quality CE in appropriate settings with adequate administrative structure.
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Delaware Academy of Ophthalmology
Does not have a web site as of April 2006
DGII: Deutschsprachige Gesellschaft für Intraokularlinsen-Implantation und refraktive Chirurgie
German speaking Society of Intraocular Lens Implantation and Refractive Surgery.
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ESCRS
European Society of Cataract & Refractive Surgeons
European Association for the Study of Diabetes. Eye Complications Study Group (EASDec)
Its AIM is to promote the advance of knowledge on all aspects of diabetic retinopathy, including epidemiology, pathology, pathophysiology and treatment of this complication of diabetes mellitus.
European Association of Eye Hospitals
10 Hospital libraries formed an association for eye hospitals. Have benchmarking guidelines.
European Board of Ophthalmology
The EBO is a permanent working group of the Ophthalmology Subspecialty Section of the European Union of Medical Specialists (UEMS). The Board oversees the standard of ophthalmic training. Residency Review Committee has a recommended list of books and journals.
European Eye Bank Association
The European Eye Bank Association (EEBA) is a technical-scientific organization comprising individual members from 83 eye banks from 22 European countries. Has a directory of members and eye bank standards. The country profiles covers Legislation and Quality Assurance matters. Related links section lists more ophthalmic associations and societies.
European Ophthalmic Pathology Society
EVER: European Association for Vision and Research
About the Association, its meetings and benefits.
Eye Bank Association of America
News and updates, Education, and how to contact the association. Includes a list of state eye banks.
Eye Health Organizations Database.
A database created by the National Eye Institute of eye health organizations.
EyeCare America
A Public Service Foundation of the American Academy of Ophthalmology.
The EyeCare Foundation
About the Foundation and it efforts toward research and treatment of Macular Degeneration, Ocular Oncology, and related Eye Diseases.
Eyegypt
Ophthalmological Society of Egypt. Information about OSE, membership, meetings, publications. Links to other sites.
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Florida Society of Ophthalmology
Website for professional ophthalmologists in Florida.
The Foundation Fighting Blindness
The Foundation's purpose is to find a cure for retinitis pigmentosa (RP), macular degeneration, Usher syndrome, and related retinal degenerative diseases.
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Georgia Society of Ophthalmology
For Georgia ophthalmologists. Litte information for public. No physicians search engine.
German Ophthalmological Society (DOG)
Deutsche Ophthalmologische Gesellschaft. A bilingual site for students, health care professionals and patients: Information about the DOG; Annual Meetings; Associated Societies and Interest Groups; Calendar of Events; Mailing lists (German speaking); Announcements/literature; eye Information (German). You may toggle between the English language and German language versions.
The Glaucoma Foundation
Describes the foundations programs and resources, information about Glaucoma, Patient Guide, Newsroom, sign up for Mailing lists, Newsletter.
Great Western Council of Optometry
GWCO EXHIBITORS: Registration, advertising and sponsorship. Member state websites.
Guide Dog Foundation for the Blind
Provides guide dogs free of charge to blind people who seek enhanced mobility and independence.
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Hawaii Ophthalmological Society
Has members directory.
Hawaii Optometric Association
For HI optometric professionals.
Heart of America Contact lens Society
Focuses on upcoming conferences,including courses, speakers, sponsors, exhibitors and online registration processes.
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Idaho Optometric Association
Has a member locator. Rest of site is for ID optometric professionals
Idaho Society of Ophthalmology
The public can find member ophthalmologists and some eye information. Members can find information about educational meetings.
Illinois Association of Ophthalmology
Does not have a web site as of April 2006.
Indiana Academy of Ophthalmology
This is a state-wide, non-profit organization for member ophthalmologists.
International Council of Ophthalmology
Resources and Connections for Prevention of Blindness: Data, Publications and Organizations. See also the Home page for the International Council of Ophthalmology. This site is the home of the database of International Ophthalmological Societies and Residency Programs and a list of Supranational and International Ophthalmologic and Subspecialty Organizations.
International Eye Foundation
Through SightReach, three programs are available: Prevention (cataract, trachoma, river blindness, and childhood blindness), Surgical, and Management.
International Foundation for Optic Nerve Disease (IFOND)
IFOND promotes research into the causes, prevention, and treatment of optic nerve disease, and to the dissemination of information about optic nerve disease. The web site is an information/support center for patients with optic nerve disease and their families, as well as clinicians, scientists and lay persons interested in optic nerve disease.
International Ophthalmology Association in the Web
Formed in 2005, it is independent, non-profit organization which aims to establish a worldwide membership and community of ophthalmologists (eye physicians and surgeons). They plan on offering free educational materials and new ideas and opportunities for continuing education and training so that to ensure the public can obtain the best possible eye care but that part of the site is still under construction (Mar, 2007).
International Perimetric Society
About Perimetry, the IPS, meeting information, IPS news, membership list, IPS proceedings and abstracts, IPS constitution, Perimetry Standards.
International Society for Eye Research (ISER)
Information about the organization, conferences sponsored by ISER and about its publication Experimental Eye Research.
International Society for Imaging in the Eye
Information about the organization
International Society for Ocular Cell Biology
Group for cell biologists working in all aspects of ocular health and disease. Meets biennially. Has a useful links page.
International Society of Refractive Surgery (ISRS)
Information for patients, locate a doctor, meeting and marketplace. Also, member's only services, member directory and ISRS interactive.
Intracranial Hypertension Research Foundation
The Intracranial Hypertension Research Foundation (IHRF) funds and supports medical research to develop better therapies to control Intracranial Hypertension (IH) while ultimately seeking a cure. The Foundation also provides support, education, and encouragement for IH patients, their families, and medical professionals.
Iowa Academy of Ophthalmology
Does not have a web site as of April 2006.
ISCEV (International Society for Clinical Electrophysiology of Vision)
Information about meetings, courses and standards. A newsletter, membership list and related links.
iSurgeon.org
Indian Ophthalmology on the web. Contains images, videos, case studies, and a discussion area.
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Kansas State Ophthalmological Society
Represents and serves the ophthalmologists of Kansas by providing CE and legislative advocacy.
Karolinska Institutet - Eye Diseases
A large site with many links to eye disease resources. Well worth the visit.
Kentucky Academy of Eye Physicians and Surgeons
Society website includes ophthalmologist locator for Kentucky.
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Library Services for Visually Impaired People: A Manual of Best Practice
This manual is designed to provide practical help for all staff who meet and serve visually impaired people during their working day. The manual draws on the experience of specialists in the field of visual impairment and of practising librarians and library managers.
Lighthouse International
Low Vision Resources and Information.
Louisiana Lions Eye Foundation, Inc.
Louisiana Ophthalmology Association
For professional ophthalmologists of LA
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Macula Society
Sponsors an annual meeting on retinal vascular and macular diseases. For researchers.
Macula Vision Research Foundation
Has eye education information.
Macular Degeneration Foundation
see also Macular Degeneration Foundation - Eyesight Vision Central Vision
Macular Degeneration International
Information about MDI as well as information about both juvenile and age-related macular degeneration written for patients and families.
Macular Degeneration Network
An educational web site for patients with macular degeneration and the health professionals who care for them. Information written for patients about treatment and prevention of MD and more.
Maine Society of Eye Physicians and Surgeons
Society website includes ophthalmologist locator for Maine.
Manitoba Association of Optometrists
Has an optometrist search engine by city. Has association links and eye information.
Maryland Society of Eye Physicians & Surgeons
Address and contact information.
Massachusetts Society of Eye Physicians and Surgeons
A non-profit organization of ophthalmologists dedicated to the public's direct access to ophthalmic care. Contains information about projects and conferences.
Michigan Ophthalmological Society
Information for members and for the public including Eye Health Topics, ophthalmologist diectory and continuing education.
Minnesota Academy of Ophthalmology
Information for members and for the public including Eye Health Topics Archives.
Mississippi Eye, Ear, Nose & Throat Association
Does not have a web site as of April 2006
Missouri Society of Eye Physicians and Surgeons
Does not have a web site as of April 2006
Montana Academy of Ophthalmology
Organizational and representative body of the medical eye physicians/surgeons in the State of Montana. Includes a membership directory.
Montana Optometric Association
Has a membership directory. Buyers guide. Information on Paraoptometric Section.
Mountain West Council of Optometrists
Information about sponsors, speakers and upcoming conferences.
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National Academy of Opticianry
Founded in 1963, the Academy offers opticianry education and training in a variety of formats. They cover all aspects of education and training from career preparation (internationally known as the Career Progression Program), certification and licensing exam preparation and continuing education for beginning through advanced level opticians.
National Association of Veterans Affairs Optometrists
Has a directory of members; residence brochure; open positions in the VA; Newsletter.
National Association for Visually Handicapped
For Patients, family and friends that need everything from large print books to the latest on their particular condition. Health Care Professionals are welcome here as well. Tips to the Visually Impaired for reconfiguring web browsers, and more.
National Board of Examiners in Optometry
Exam guide, exam schedule, application, Test Points and National Board Articles.
National Eye Institute
The National Eye Institute (NEI) was established by Congress in 1968 to protect and prolong the vision of the American people. The NEI conducts and supports research that helps prevent and treat eye diseases and other disorders of vision. This research leads to sight-saving treatments, reduces visual impairment and blindness, and improves the quality of life for people of all ages. NEI-supported research has advanced our knowledge of how the visual system functions in health and disease. NEI has an Eye Health Organizations Database.
National Federation of Opticianry Schools
National Keratoconus Foundation
About keratoconus, research overview, a newsletter, and other keratoconus links, Also, information about the Foundation.
National Optometric Association
An organization for optometry students and optometrists who are classified as a minority.
National Sjogren's Syndrome Association
About the organization, Finding Help, Symptoms/Information, related diseases.
Nebraska Academy of Eye Physicians and Surgeons
Does not have a web site as of April 2006
The Neuro Optometric Rehabilitation Association (NORA)
Information for patients and professionals. Patient information articles run the gamut from visual hallucinations to convergence insufficiency syndrome.
Nevada Ophthalmological Society
Does not have a web site as of April 2006
Nevada Optometric Association
Has a NV optometry search engine.
New Brunswick Association of Optometrists
Has a doctor search engine; Some information on eye safety and healthy eyes.
New Hampshire Society of Eye Physicians and Surgeons
Does not have a web site as of April 2006
New Jersey Academy of Ophthalmology
Has a directory search for NJ ophthalmologists and lists websites for eye organizations.
New Jersey Society of Optometric Physicians
Eyecare & eyewear information for consumers as well as providing a comprehensive on-line resource and reference library for New Jersey's optometrists.
New Mexico Ophthalmological Society
Directory of NM ophthalmologists; eye information from Medem network.
New York State Ophthalmological Society
Has a member directory to find ophthalmologists in NY. Has a What's New page and links to insurance forms and coding.
New Zealand Society of Contact Lens Practitioners
A wide ranging resource with many relevant links.
Newfoundland and Labrador Association of Optometrists
Has a doctor search engine; Some information on eye safety and healthy eyes. Has links to other Canadian provincial optometric organisations.
NOAH (National Organization for Albinism and Hypopigmentation) Albinism and Hypopigmentation
The purpose of this page is to provide information about albinism and NOAH (National Organization for Albinism and Hypopigmentation). This page is also for members of NOAH to post announcements of meetings and social events, and tell their success stories.
NOAH (New York Online Access to Health): Eyes and Low Vision
New York Online Access to Health. Links to sites about the eye especially selected for patients and the general public. En Español: los ojos y la visión
North American Neuro-Ophthalmology Society (NANOS)
Professional Society information for members as well as some patient informational brochures on such topics as migraines, myasthenia gravis, pseudotumor cerebri, and thyoid eye disease.
North Carolina Society of Eye Physicians and Surgeons
Has an extensive links page and NC legislative section.
North Dakota Society of Eye Physicians and Surgeons
Does not have a web site as of April 2006
Northern Rockies Optometric Conference
Has annual meeting information; patient education information; and a doctor's search.
The Nova Scotia Association of Optometrists
Has search engine for NS optometrists. Has eye information.
Nystagmus Network
Information about nystagmus.
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Ocular Heritage Society
For members who appreciate, conserve and collect items relating to the ophthalmic sciences. Has information on French spectacles from 1800.
Ocular Motor Apraxia
Written for the layperson concerned about OMA.Support groups, mailing list, message board, a bibliography about OMA.
Ocular Microbiology and Immunology Group (OMIG
Contact information, OMIG meetings, and helpful links for members.
Ocularists Association of Australia
The Ocularists Association of Australia was founded as a way to ensure a high standard of service and care for artificial eye recipients in Australia. Includes a mission statement and code of ethics. Standards are under development. Some support groups are listed.
Ohio Ophthalmological Society
About the organization, membership and legislation. Also community resources, practice management, educational opportunities and related links.
Oklahoma Academy of Ophthalmology
Oklahoma ophthalmologist directory. Has legislative information and some internet links.
Ontario Association of Optometrists
Has an optometry search engine and eye information.
Ophthalmic Photographers' Society
Besides having information about OPS, this sites contains helpful information about Ophthalmic photography, abundant images, Chapters about types of ophthalmic imaging and what it can reveal.
Optical Laboratories Association
An international business association founded in 1894 to serve the needs of the optical laboratory industry. OLA produces a variety of education and training materials for optical laboratories and eyecare professionals and it sponsors and administers the ANSI Z80 Committee and serves as the ANSI Z80 Secretariat.
The Optical Society of America
The mission of OSA is to promote the generation, application and archiving of knowledge in optics and photonics and to disseminate this knowledge worldwide.
The Opticians Association of America
Opticians Association of America general information, membership information, optician forum, information about continuing education, web site announcements.
The Opticians Association of Canada
Has sections for professional opticians, student opticians and the consumer.
Optometric Extension Program Foundation
The OEP is an international, non-profit organization dedicated to the gathering and dissemination of information on Vision.
Optometric Historical Society
An organization for persons interested in the history of optometry, spectacle lenses, vision science, or related topics.
Optometric Physicians of Washington
Has eye health information and an optometric physician's search engine.
ORBIS International
About the organization. ORBIS is a nonprofit, humanitarian organization dedicated to preserving and restoring sight in the developing world. Through innovative programs and partnerships, ORBIS produces long-term, sustainable solutions to preventable blindness that emphasize training of medical personnel, strengthening of in-country eye care institutions, and expanding delivery of quality eye care and prevention strategies in those parts of the world where the need is greatest.
Oregon Academy of Ophthalmology
About the academy, educational opportunities and the way of serving three audiences: public, members and other Ophthalmologists. Includes a search engine to find ophthalmologists.
Oregon Optometric Physicians Association
Has eye health information and an optometric physician's search engine.
Orthokeratology Academy of America
Has online version of The Corrected View, its journal. Serves orthokeratologists around the world. Has some consumer links and a professional membership page.
Orthoptic Association of Australia, Inc. (OAA)
About Orthoptics, the association and conferences offered through OAA.
Orthoptics Online
American Association of Certified Orthoptics and The American Orthoptic Council website with Continuting Opportunities, training programs, the American Orthoptic Journal and more.
Outpatient Ophthalmic Surgery Society
Providing education, information, and advocacy with government agencies for its members and their ASCs. Helping ASC owners and ophthalmic surgeons utilizing ASCs provide high quality, cost-effective surgical care.
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Pan-American Association of Ophthalmology
Non-profit organization whose mission is the continuing education of ophthalmologists, the prevention of blindness, and the promotion of scientific and cultural exchange among ophthalmologists in the Western Hemisphere and the world.
Pediatric Keratoplasty Association
An association dedicated to the study of Pediatric Keratoplasty. Site includes Physician and eye information areas, research information, newsletters, meeting information for physicians and an interactive web board.
Pennsylvania Academy of Ophthalmology
An association of "Eye MDs". Some eye information. Calendar of events. Internet links to ophthalmic groups.
Prevent Blindness America
National voluntary health agency working to prevent blindness. The site contains Eye Facts and Fun, including Eye Health and Safety Tips, Glaucoma Information, and the Effects of Computers on Your Eyes.
Prince Edward Island Association of Optometrists
Has an eye doctor search engine; information on eye safety and eye health.
Puerto Rico Ophthalmological Society
Web site in Spanish language. Directory search for ophthalmologist. Some eye information.
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Retina Australia
Retina Australia, Inc., formerly The Retinitis Pigmentosa Society (RP Society), represents people who live with retinitis pigmentosa and other retinal dystrophies. These are degenerative diseases causing low vision and a gradual deterioration of a person's sight. The work of RA Inc. is carried out predominantly by volunteers, many who are vision impaired and know the implications of vision loss. Retina Australia is committed to raising funds to support research into treatments and a cure for RP and all other retinal dystrophies.
Retina International
Retina International (formerly known as the International Retinitis Pigmentosa Assoc. - IRPA) is a voluntary charitable umbrella association of 34 national societies each of which is formed by people with Retinitis pigmentosa (RP), Usher Syndrome, Macular Degeneration and allied retinal dystrophies, their families and friends.
Retina Society
Has a directory of members. Sponsors an annual meeting.
Rhode Island Society of Eye Physicians and Surgeons
Does not have a web site as of April 2006
ROPARD: Association for Retinopathy of Prematurity and Related Retinal Diseases
About ROP, information and links for parents, videos, and a newsletter.
Royal National Institute for the Blind , UK
London based Royal National Institute for the Blind. UK’s leading charity offering information, support and advice to over two million people with sight problems. Helps anyone with a sight problem – not just with braille, Talking Books and computer training, but with imaginative and practical solutions to everyday challenges. Funds pioneering research into preventing and treating eye disease.
Royal Victorian Institute for the Blind
RVIB, Melbourne, Australia. RVIB has been providing services, resources and support to Victorians who are blind or vision impaired so that they may lead full and independent lives.
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Saskatchewan Association Of Optometrists
Association of Optometrists providing eyecare. Has an optometrist search engine and eye information
SIDUO
Societas Internationalis Pro Diagnostica Ultrasonica in Ophthalmologia, International Ophthalmic Echography Organization
Sjogren's Syndrome Foundation, Inc.
The Foundation provides patients practical information and coping strategies that minimize the effects of Sjögren's syndrome. In addition, the Foundation is the clearinghouse for medical information and is the recognized national advocate for Sjögren's syndrome.
SNOF: Syndicat National des Ophtalmologistes de France
Especially see the photothèque.
Sociedad Colombiana de Oftalmologia
The Society of ophthalmologists from Colombia, South America. Their purpose is to aid the development of scientific aspects of ophthalmology. It includes a vision science journal list, information on practice patterns. The website is in Spanish.
Societas Internationalis Pro Diagnostica Ultrasonica in Ophthalmologia: See SIDUO
Society of Military Ophthalmologists
A society for active duty and former or retired ophthalmologists of the U. S. Army, Air Force, Navy, and Public Health Service with some helpful links.
South Carolina Society of Ophthalmology
South Carolina's Eye MDs. The activities of this society and some internet links.
Southern Council of Optometrists
SoCO is comprised of the state associations of the following states: Alabama, Arkansas, Florida, Georgia, Kentucky, Louisiana, Mississippi, North Carolina, South Carolina, Tennessee, Virginia and West Virginia. The corporation name is SECO International.
South Dakota Academy of Ophthalmology
Does not have a web site as of April 2006
SPIE: International Society for Optical Engineering
SPIE is a not-for-profit society that has become the largest international force for the exchange, collection and dissemination of knowledge in optics, photonics and imaging.
Surgical Eye Expeditions (S.E.E.) International
Surgical Eye Expeditions (SEE) International, Inc. is a non-profit humanitarian organization that provides medical, surgical and educational services by volunteer ophthalmic surgeons with the primary objective of restoring sight to disadvantaged blind individuals worldwide.
Surgical Eyes Foundation
Surgical Eyes™ is an organization founded by people with longer-term complications from refractive surgery to assist others who have had unsuccessful LASIK, LASEK, PRK, RK, AK, ALK or other elective refractive surgeries. We help identify current remedies and spur development of future technologies to help us overcome our surgically created visual difficulties...
Swiss Orthoptics SVO/ASO
Syndicat National des Ophtalmologistes de France
Phototheque, Annonces, Conges, Art, Histoire, Liens.
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Talking Newspaper Association, UK
for people with Low Vision.
Tear Film & Ocular Surface Society
Purpose is to advance the research, literacy & educational aspects of the scientific field of the tearfilm and ocular surface.
Tennessee Academy of Ophthalmology
About the Academy, their education and the provided resources of assistance. Includes an ophthalmologist search engine.
Texas Ophthalmological Association
Online search directory for ophthalmologists. Includes legislative information.
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Unite for Sight
A nonprofit organization that empowers communities worldwide to improve eye health and eliminate preventable blindness.
Utah Ophthalmological Society
Provides public information as well as updates members and other ophthalmic professionals on current news and educational opportunities. Online Directory of members.
Utah Optometric Association
Has a doctor locator. Has a market place and calendar of events.
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Verband der Spezialkliniken Deutschlands für Augenlaser und Refraktive Chirurgie e.V.
Der Verband der Spezialkliniken Deutschlands fuer Augenlaser und Refraktive Chirurgie e.V. (VSDAR) hat es sich zum Ziel gesetzt, umfassend ueber die operativen Methoden zur Korrektur der Fehlsichtigkeiten zu informieren und aufzuklaeren. Ausserdem unterstuetzt er seine Mitglieder bei der Qualitaetssicherung sowie der Weiterentwicklung der eingesetzten Verfahren.
[German Language. The Association of German Clinics for Eye Laser and Refractive Surgery (VSDAR) attempts to educate and inform patients about the opportunities of operative vision correction. Furthermore, the association supports its members in quality assurance issues and the further development of the treatment.]
Vermont Ophthalmological Society
Does not have a web site as of April 2006
Virginia Society of Ophthalmology
Nonprofit organization committed to heightening public awareness that eye disease and blindness can be reduced through prevention, and early detection and treatment. Online Newsletter. Some internet links.
Vision Council of America / Better Vision Institute
VCA is the largest nonprofit trade association that represents the interests of the entire optical community. Members of VCA are those which sell optical products in North America and exhibit at International Vision Expo East, International Vision Expo West, and EyeQuest. VCA has four categories of membership. Full Membership, Associate Membership, Exhibitor Membership and Trade Media Membership.
Vision of Children
One of the organization's goals is to disseminate information about the detection, incidence, and treatment of diseases or conditions that either severely impair vision or cause total blindness in children. The site addresses ocular albinism and other hereditary diseases affecting the eye.
Volunteer Optometric Services to Humanity: See VOSH International
VOSH International
Provides vision care worldwide to people who can neither afford nor obtain such care. Newsletter available.
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Washington Academy of Eye Physicians and Surgeons
Ophthalmologist search engine. Medem eye health library link. Includes meeting information.
Washington DC Metropolitan Ophthalmological Society
Has search engine for DC ophthalmologists. Helpful websites for the public.
West Virginia Academy of Ophthalmology
About WVAO, their events and education with some featured links.
Wisconsin Academy of Ophthalmology
Does not have a web site as of April 2006
Women in Ophthalmology
About this organization, it's goals and a listing of their events through 2004.
World Council of Optometry
The World Council of Optometry (WCO) is an international organization dedicated to the enhancement and development of eye and vision care worldwide. Representing over 50 countries, WCO serves as a forum for member organizations to respond to public health needs and opportunities around the world.
Wyoming Ophthalmological Society
Does not have a web site as of April 2006
Wyoming Optometric Association
Has patient eye information and a doctor's search.
AAOSE
American Association for Ophthalmic Standardized Echography
AAPOS Home Page
American Association for Pediatric Ophthalmology and Strabismus. A resource for Pediatric Ophthalmologists, Strabismologists, related personnel and patients.
Alabama Academy of Ophthalmology
ALAO website is a trade association made up of ophthalmologists who are licensed and practicing in the state of Alabama,and Corporate representatives who provide goods or services of value to ophthalmologists .
Alaska Optometric Physicians Association
News, meetings,web links, and directory search of optometrists.
Alaska State Ophthalmological Society
does not have a website as of April 2006.
Alberta Association of Optometrists
Website for professional optometrists in Alberta, Canada. It includes eyecare information.
All India Ophthalmological Society
Conference abstracts, CME, Full text journal articles, membership directory, newsletter and more. (may be slow to load).
AMD Alliance International
A global coalition of vision and seniors' organizations dedicated to the raising awareness of AMD and the options available for prevention, early detection, treatment, rehabilitation and support services.
AMDF: American Macular Degeneration Foundation
American Academy of Ophthalmology
This site serves the professional needs of the Academy's members.
American Academy of Optometry
About membership services, the Annual Meeting, News, additional links.
American Academy of Optometry, British Chapter
Tutorials and pages upon pages of Information for, by or about Optometrists and Optometry.
American Academy of Pediatrics. Section on Ophthalmology
Provides an educational forum for the discussion of problems and treatments related to ophthalmology in children. Includes pdf files of published policy statements.
American Association for Pediatric Ophthalmology and Strabismus
American Association for Pediatric Ophthalmology and Strabismus. A resource for Pediatric Ophthalmologists, Strabismologists, related personnel and patients.
American Association of Ophthalmic Pathologists
A professional association of medical doctors who practice, teach and or engage in research in ophthalmic pathology.
American Board of Ophthalmology
History of the Board, Mission and intent, Examination Statistics, Applications, Requirements, Dates and Deadlines, Requirements for Recertification. Links to the American Board of Medical Specialties.
American College of Veterinary Ophthalmologists
ACVO is the association that establishes criteria for certifying veterinary ophthalmologists. Site contains profiles of diplomates, areas for professionals and for the public, a calendar of events, news items and related links.
American Foundation for the Blind
Information about the organization, its services and publications. Includes the AFB Directory of Services for Blind and Visually Impaired Persons in the United States and Canada. Locate organizations in the United States and Canada that provide services to people who are blind or visually impaired and their families. The Services Center is based on the AFB Directory of Services for Blind and Visually Impaired Persons in the United States and Canada. You can use the Services Center to find a service provider by name, state, country, or service category.
American Glaucoma Sociey
Promotes excellence in the care of patients with glaucoma and preserves or enhances vision by supporting glaucoma specialists and scientists through the advancement of education and research. Has physician and patient resource centers.
American Nystagmus Network
Information about Nystagmus, links to a discussion group, ANN conferences. The Site Map is helpful in navigating the site.
American Ophthalmological Society
Promotes excellence in patient care, education and research, to address essential issues in medicine, and to advance the art and science of ophthalmology. Transactions are available online.
American Optometric Association
About the AOA. Common eye conditions and diseases, children's vision, contact lens information, sports & vision, eyecare tips, an educations center (for kids, for teachers and for people considering optometry as a career). Recent press releases
American Optometric Foundation
The foundation for the American Academy of Optometry.
American Osteopathic College of Ophthalmology
Profesional site for Osteopathic ophthalmologists. Includes directory of members and FAQ for patients.
American Public Health Association, Vision Care Section
The VCS serves as an advocate to ensure equality in, and access to, vision and eye health care, and to ensure inclusion of vision in public health policy. Websiter contains information about the organization and resolutions, a list of officers and upcoming events.
American Retina Foundation
For patient education about retinal problems. Supported by Alcon grant. Physicans search service.
American Society of Ocularists
The American Society of Ocularists is an international, non-profit, professional and educational organization founded in 1957 by technicians specializing in the fabricating and fitting of custom-made ocular prosthetics (artificial eyes).
American Society of Cataract & Refractive Surgery
Members have access to images. Surgeon search service. Has meeting and government relations sections.
American Society of Ophthalmic Plastic & Reconstructive Surgery: ASOPRS
Membership directory, Information about ophthalmic plastic and reconstructive surgery: eyelid, orbit, eye, lacrimal, cosmetic surgery, oculoplastics, prosthesis, trauma, blepharoplasty, blepharospasm, thyroid eye disease, laser, facial surgery, fractures, congenital deformities, fellowship information. The site index is very helpful
American Society of Ocularists
An international, non-profit, professional and educational organization founded in 1957 by professionals specializing in the fabricating and fitting of custom-made ocular prosthetics (artificial eyes). Has a search engine to locate ocularists. FAQ's listed under Resources.
American Society of Ophthalmic Administrators
The ASOA is a membership organization focusing on the business of ophthalmology. They publish Administrative Eye Care and offer Certification of Ophthalmic Executives. They offer online courses in administration.
American Society of Retina Specialists
Information about the society, its meetings and publications (including the online journal). Listserver information (for members). Disease Information (Information about Age-Related Macular Degeneration. Physicians search service.
American Society of Veterinary Ophthalmologists
American Uveitis Society
Resource for individuals with an interest in inflammatory eye diseases, including patients, families, researchers, ophthalmologists and other healthcare providers.
Aravind Eye Care System
WHO collaborating centre for prevention of blindness located in Madurai, Theni, Tirunelveli Coimbatore, and Pondicherry, India. See the Aravind Eyesite, an online collection of comprehensive resources for eye care programs around the world. It shares tools that help plan, implement, manage and assess high quality, efficient, and sustainable eye care programs in the developing world.
Arizona Ophthalmological Society
Serves as a source of educational, social, and ethical exchange for the member Eye MDs of the State of Arizona. Has a member's directory.
Arizona Optometric Association
Search of AZ optometrists, Some patient education and professional opportunities.
Arkansas Ophthalmological Society
Promotes and advances the science and art of medical eye care. Has information for public and ophthalmologists.
Armed Forces Optometric Society
Lists officers and mission statement. Has some web links.
ARVO
The Association for Research in Vision and Ophthalmology (ARVO).
ASCRS - ASOA
American Society of Cataract and Refractive Surgery. Site of EyeWorld news service.
ASOPRS: see American Society of Ophthalmic Plastic & Reconstructive Surgery
ASORN
American Society of Ophthalmic Registered Nurses. Information about the organization and its publications, services and products, Information about Certification.
ASRS: see American Society of Retina Specialists
Association for Macular Diseases, Inc.
About the association, a monthly newsletter and more.
Association des optométristes du Québec
Web site in French. Sections for general public and optometrists.
Association for Ocular Pharmacology and Therapeutics
Hosts biennial meetings. For vision scientists interested in the exchange of information about ocular pharmacology. Publishes the Journal of Ocular Pharmacology and Therapeutics.
Association of Optometric Contact Lens Educators
The Association of Optometric Contact Lens Educators is committed to fostering the highest levels of education in the areas of cornea and contact lenses and supporting the faculty in these areas at each of the North American schools and colleges of optometry..
Association of Optometrists (London, England)
Promotes the professional and clinical independence of its members and the profession .
Association of Regulatory Boards of Optometry
The Association of Regulatory Boards of Optometry (ARBO) is the federation of state, provincial, and territorial boards of optometry throughout North America. Boards of optometry serve as the licensing and regulatory arm of the optometric profession by formulating rules, or regulations, that govern and enforce the laws that grant the privilege to practice optometry, which are enacted by state legislatures.
Association of Schools and Colleges of Optometry
ASCO's website lists Accredited Schools and College of Optometry, residency sites, optometric faculty directory, FAQ about optometry and links to related sites.
Association of Technical Personnel in Ophthalmology
Association of University Professors of Ophthalmology
Represents academic departments of ophthalmology with open positions and a newsletter.
Association of Veterans Affairs Ophthalmologists
Has a membership listing and pdf copies of newsletters.
Association of Vision Science Librarians (AVSL)
The Association of Vision Science Librarians is an international organization composed of professional librarians, or persons acting in that capacity, whose collections and services include the literature of vision. Among current members are individuals who work within libraries that serve educational institutions, eye clinics and hospitals, and private companies with an interest in eye or vision-related products and services. The Association is a Special Interest Group of both the Association of Schools and Colleges of Optometry and the Medical Library Association. Site includes: Publications: Standards, Guidelines, Union List of Vision-Related Serials, Opening Day Book Collection, Core List Audio-Visual Collection, Publication Considerations in the Age of Electronic Opportunities. Includes links to a Subject Guide to Internet Resources in Vision Science, a list of Spanish Language Books, E-Books & Journals, CD-ROM Titles in Vision Science, Directories & Statistical Sources, Eye Care Statistics, and Library Catalogs.
AVSL: see Association of Vision Science Librarians
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Belgian Society of Ophthalmology
Multi-lingual site with information about the organization, its publications, congresses, and links to other sites. It has an extensive calendar of ophthalmology events and congresses that is well worth the visit.
Beta Sigma Kappa
International Optometric Honor Society
Brazilian Society of Laser and Ophthalmic Surgery
Alternative name: Brazilian Laser Ophthalmological Surgery Society. An official society of the Brazilian Council of Ophthalmology. (may be slow to load)
British Columbia Association of Optometrists
The voice of Optometrists across the province;it is prominently affiliated with provincial, national and government organizations
British Computer Association of the Blind
British Contact Lens Association
About the association. Clinical Conference announcements, continuing education sourses and scientific meetings.
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California Academy of Ophthalmology
Serves the total visual health care needs of the people through public and professional education, membership services, and legislative advocacy. It is dedicated to the public's direct access to an ophthalmologist's care.
California Optometric Association
For CA professionals. Includes calendar of events.
Canadian Association of Optometrists
CAO is the professional association that represents Doctors of Optometry in Canada. It is also the national federation of ten provincial associations of optometrists and represents over 3,200 members across Canada. This site is committed to providing quality information about Optometry, the national association, and vision and eye health.
Canadian Examiners in Optometry (CEO)
Canadian Examiners in Optometry (CEO) is a not-for-profit corporation whose shareholders are the ten provincial Regulators. CEO was created by the Regulators to address matters of common interest. These include 1)describing the profession as practised in Canada, including describing quality practice, 2)assessing the competence of individual optometrists in the practice of optometry and providing the assessment results to the individuals and to relevant regulators, 3)providing mechanisms to evaluate the quality of practice of optometrists in Canada.
Canadian Ophthalmological Society (COS)
(Eyesite.ca) About the society, its programs, services and affiliations as well as a calendar of events, and information for the public.
The Canadian Orthoptic Society (TCOS)
CareerMD
Current information on practice opportunities in Ophthalmology and Ophthalmology Subspecialties (and other specialties). Listings have been submitted by employers who are interested in reaching current Ophthalmology residents and fellows. Each posting includes a brief description of the opportunity, as well as contact information for all inquiries.
Center for the Partially Sighted
Promotes independent living for people of all ages with impaired sight.
College of Optometrists (London, England)
The College of Optometrists is the Professional, Scientific and Examining Body for Optometry in the UK working for the public benefit.
College of Optometrists in Vision Development
St. Louis, Missouri. This site includes a library of articles about many vision conditions and treatments, also information about the organization and links to other sites.
Colorado Society of Eye Physicians and Surgeons
An organization for Colorado ophthalmologists. Sponsors CE and advocates legislative actions.
Commission on Opticianry Accreditation
COA is the organization recognized by the U.S. Department of Education to accredit Opticianry training in the United States.
Connecticut Society of Eye Physicians and Surgeons
Represents more than 300 ophthalmologists in the State of Connecticut - and their patients. It has programs for education and advocacy.
Contact Lens Association of Ophthalmologists
CLAO's mission is to advance quality medical eye care for the public by providing comprehensive ophthalmologists and other eye care professionals with education and training in contact lenses and related eye care science.
Contact Lens Council
Glossary, Contact Lens History, Contact Lens FAQ, Health and Safety.
Contact Lens Society of America
Has a member search engine. Sponsors an annual meeting and CE courses. It is dedicated to the education, evolution, and promotion of contact lens technology.
Cornea Society
Information for professionals.
Council for Refractive Surgery Quality Assurance
CRSQA is a nonprofit consumer/patient health organization that certifies surgeons who perform eye surgery to eliminate glasses. Extensive information regarding refractive surgery. Links to certified surgeons and other vision related websites.
Council on Optometric Practitioner Education (COPE)
COPE is a committee of the Association of Regulatory Boards of Optometry (ARBO), which is the association that currently represents 50 US optometry boards, 4 US territories/jurisdictions, and 2 Canadian boards. Its mission is to: 1)coordinate the review and approval of continuing optometric education courses on behalf of state boards on a national basis; 2)reduce duplication of effort by state boards; 3)create a uniform method of recording continuing education courses on a national basis; 4)be the clearinghouse for information about continuing education programs and courses utilized by licensed optometrists to fulfill their continuing education requirements for license renewal; and 5) encourage program sponsors to offer high quality CE in appropriate settings with adequate administrative structure.
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Delaware Academy of Ophthalmology
Does not have a web site as of April 2006
DGII: Deutschsprachige Gesellschaft für Intraokularlinsen-Implantation und refraktive Chirurgie
German speaking Society of Intraocular Lens Implantation and Refractive Surgery.
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ESCRS
European Society of Cataract & Refractive Surgeons
European Association for the Study of Diabetes. Eye Complications Study Group (EASDec)
Its AIM is to promote the advance of knowledge on all aspects of diabetic retinopathy, including epidemiology, pathology, pathophysiology and treatment of this complication of diabetes mellitus.
European Association of Eye Hospitals
10 Hospital libraries formed an association for eye hospitals. Have benchmarking guidelines.
European Board of Ophthalmology
The EBO is a permanent working group of the Ophthalmology Subspecialty Section of the European Union of Medical Specialists (UEMS). The Board oversees the standard of ophthalmic training. Residency Review Committee has a recommended list of books and journals.
European Eye Bank Association
The European Eye Bank Association (EEBA) is a technical-scientific organization comprising individual members from 83 eye banks from 22 European countries. Has a directory of members and eye bank standards. The country profiles covers Legislation and Quality Assurance matters. Related links section lists more ophthalmic associations and societies.
European Ophthalmic Pathology Society
EVER: European Association for Vision and Research
About the Association, its meetings and benefits.
Eye Bank Association of America
News and updates, Education, and how to contact the association. Includes a list of state eye banks.
Eye Health Organizations Database.
A database created by the National Eye Institute of eye health organizations.
EyeCare America
A Public Service Foundation of the American Academy of Ophthalmology.
The EyeCare Foundation
About the Foundation and it efforts toward research and treatment of Macular Degeneration, Ocular Oncology, and related Eye Diseases.
Eyegypt
Ophthalmological Society of Egypt. Information about OSE, membership, meetings, publications. Links to other sites.
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Florida Society of Ophthalmology
Website for professional ophthalmologists in Florida.
The Foundation Fighting Blindness
The Foundation's purpose is to find a cure for retinitis pigmentosa (RP), macular degeneration, Usher syndrome, and related retinal degenerative diseases.
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Georgia Society of Ophthalmology
For Georgia ophthalmologists. Litte information for public. No physicians search engine.
German Ophthalmological Society (DOG)
Deutsche Ophthalmologische Gesellschaft. A bilingual site for students, health care professionals and patients: Information about the DOG; Annual Meetings; Associated Societies and Interest Groups; Calendar of Events; Mailing lists (German speaking); Announcements/literature; eye Information (German). You may toggle between the English language and German language versions.
The Glaucoma Foundation
Describes the foundations programs and resources, information about Glaucoma, Patient Guide, Newsroom, sign up for Mailing lists, Newsletter.
Great Western Council of Optometry
GWCO EXHIBITORS: Registration, advertising and sponsorship. Member state websites.
Guide Dog Foundation for the Blind
Provides guide dogs free of charge to blind people who seek enhanced mobility and independence.
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Hawaii Ophthalmological Society
Has members directory.
Hawaii Optometric Association
For HI optometric professionals.
Heart of America Contact lens Society
Focuses on upcoming conferences,including courses, speakers, sponsors, exhibitors and online registration processes.
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Idaho Optometric Association
Has a member locator. Rest of site is for ID optometric professionals
Idaho Society of Ophthalmology
The public can find member ophthalmologists and some eye information. Members can find information about educational meetings.
Illinois Association of Ophthalmology
Does not have a web site as of April 2006.
Indiana Academy of Ophthalmology
This is a state-wide, non-profit organization for member ophthalmologists.
International Council of Ophthalmology
Resources and Connections for Prevention of Blindness: Data, Publications and Organizations. See also the Home page for the International Council of Ophthalmology. This site is the home of the database of International Ophthalmological Societies and Residency Programs and a list of Supranational and International Ophthalmologic and Subspecialty Organizations.
International Eye Foundation
Through SightReach, three programs are available: Prevention (cataract, trachoma, river blindness, and childhood blindness), Surgical, and Management.
International Foundation for Optic Nerve Disease (IFOND)
IFOND promotes research into the causes, prevention, and treatment of optic nerve disease, and to the dissemination of information about optic nerve disease. The web site is an information/support center for patients with optic nerve disease and their families, as well as clinicians, scientists and lay persons interested in optic nerve disease.
International Ophthalmology Association in the Web
Formed in 2005, it is independent, non-profit organization which aims to establish a worldwide membership and community of ophthalmologists (eye physicians and surgeons). They plan on offering free educational materials and new ideas and opportunities for continuing education and training so that to ensure the public can obtain the best possible eye care but that part of the site is still under construction (Mar, 2007).
International Perimetric Society
About Perimetry, the IPS, meeting information, IPS news, membership list, IPS proceedings and abstracts, IPS constitution, Perimetry Standards.
International Society for Eye Research (ISER)
Information about the organization, conferences sponsored by ISER and about its publication Experimental Eye Research.
International Society for Imaging in the Eye
Information about the organization
International Society for Ocular Cell Biology
Group for cell biologists working in all aspects of ocular health and disease. Meets biennially. Has a useful links page.
International Society of Refractive Surgery (ISRS)
Information for patients, locate a doctor, meeting and marketplace. Also, member's only services, member directory and ISRS interactive.
Intracranial Hypertension Research Foundation
The Intracranial Hypertension Research Foundation (IHRF) funds and supports medical research to develop better therapies to control Intracranial Hypertension (IH) while ultimately seeking a cure. The Foundation also provides support, education, and encouragement for IH patients, their families, and medical professionals.
Iowa Academy of Ophthalmology
Does not have a web site as of April 2006.
ISCEV (International Society for Clinical Electrophysiology of Vision)
Information about meetings, courses and standards. A newsletter, membership list and related links.
iSurgeon.org
Indian Ophthalmology on the web. Contains images, videos, case studies, and a discussion area.
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Kansas State Ophthalmological Society
Represents and serves the ophthalmologists of Kansas by providing CE and legislative advocacy.
Karolinska Institutet - Eye Diseases
A large site with many links to eye disease resources. Well worth the visit.
Kentucky Academy of Eye Physicians and Surgeons
Society website includes ophthalmologist locator for Kentucky.
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Library Services for Visually Impaired People: A Manual of Best Practice
This manual is designed to provide practical help for all staff who meet and serve visually impaired people during their working day. The manual draws on the experience of specialists in the field of visual impairment and of practising librarians and library managers.
Lighthouse International
Low Vision Resources and Information.
Louisiana Lions Eye Foundation, Inc.
Louisiana Ophthalmology Association
For professional ophthalmologists of LA
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Macula Society
Sponsors an annual meeting on retinal vascular and macular diseases. For researchers.
Macula Vision Research Foundation
Has eye education information.
Macular Degeneration Foundation
see also Macular Degeneration Foundation - Eyesight Vision Central Vision
Macular Degeneration International
Information about MDI as well as information about both juvenile and age-related macular degeneration written for patients and families.
Macular Degeneration Network
An educational web site for patients with macular degeneration and the health professionals who care for them. Information written for patients about treatment and prevention of MD and more.
Maine Society of Eye Physicians and Surgeons
Society website includes ophthalmologist locator for Maine.
Manitoba Association of Optometrists
Has an optometrist search engine by city. Has association links and eye information.
Maryland Society of Eye Physicians & Surgeons
Address and contact information.
Massachusetts Society of Eye Physicians and Surgeons
A non-profit organization of ophthalmologists dedicated to the public's direct access to ophthalmic care. Contains information about projects and conferences.
Michigan Ophthalmological Society
Information for members and for the public including Eye Health Topics, ophthalmologist diectory and continuing education.
Minnesota Academy of Ophthalmology
Information for members and for the public including Eye Health Topics Archives.
Mississippi Eye, Ear, Nose & Throat Association
Does not have a web site as of April 2006
Missouri Society of Eye Physicians and Surgeons
Does not have a web site as of April 2006
Montana Academy of Ophthalmology
Organizational and representative body of the medical eye physicians/surgeons in the State of Montana. Includes a membership directory.
Montana Optometric Association
Has a membership directory. Buyers guide. Information on Paraoptometric Section.
Mountain West Council of Optometrists
Information about sponsors, speakers and upcoming conferences.
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National Academy of Opticianry
Founded in 1963, the Academy offers opticianry education and training in a variety of formats. They cover all aspects of education and training from career preparation (internationally known as the Career Progression Program), certification and licensing exam preparation and continuing education for beginning through advanced level opticians.
National Association of Veterans Affairs Optometrists
Has a directory of members; residence brochure; open positions in the VA; Newsletter.
National Association for Visually Handicapped
For Patients, family and friends that need everything from large print books to the latest on their particular condition. Health Care Professionals are welcome here as well. Tips to the Visually Impaired for reconfiguring web browsers, and more.
National Board of Examiners in Optometry
Exam guide, exam schedule, application, Test Points and National Board Articles.
National Eye Institute
The National Eye Institute (NEI) was established by Congress in 1968 to protect and prolong the vision of the American people. The NEI conducts and supports research that helps prevent and treat eye diseases and other disorders of vision. This research leads to sight-saving treatments, reduces visual impairment and blindness, and improves the quality of life for people of all ages. NEI-supported research has advanced our knowledge of how the visual system functions in health and disease. NEI has an Eye Health Organizations Database.
National Federation of Opticianry Schools
National Keratoconus Foundation
About keratoconus, research overview, a newsletter, and other keratoconus links, Also, information about the Foundation.
National Optometric Association
An organization for optometry students and optometrists who are classified as a minority.
National Sjogren's Syndrome Association
About the organization, Finding Help, Symptoms/Information, related diseases.
Nebraska Academy of Eye Physicians and Surgeons
Does not have a web site as of April 2006
The Neuro Optometric Rehabilitation Association (NORA)
Information for patients and professionals. Patient information articles run the gamut from visual hallucinations to convergence insufficiency syndrome.
Nevada Ophthalmological Society
Does not have a web site as of April 2006
Nevada Optometric Association
Has a NV optometry search engine.
New Brunswick Association of Optometrists
Has a doctor search engine; Some information on eye safety and healthy eyes.
New Hampshire Society of Eye Physicians and Surgeons
Does not have a web site as of April 2006
New Jersey Academy of Ophthalmology
Has a directory search for NJ ophthalmologists and lists websites for eye organizations.
New Jersey Society of Optometric Physicians
Eyecare & eyewear information for consumers as well as providing a comprehensive on-line resource and reference library for New Jersey's optometrists.
New Mexico Ophthalmological Society
Directory of NM ophthalmologists; eye information from Medem network.
New York State Ophthalmological Society
Has a member directory to find ophthalmologists in NY. Has a What's New page and links to insurance forms and coding.
New Zealand Society of Contact Lens Practitioners
A wide ranging resource with many relevant links.
Newfoundland and Labrador Association of Optometrists
Has a doctor search engine; Some information on eye safety and healthy eyes. Has links to other Canadian provincial optometric organisations.
NOAH (National Organization for Albinism and Hypopigmentation) Albinism and Hypopigmentation
The purpose of this page is to provide information about albinism and NOAH (National Organization for Albinism and Hypopigmentation). This page is also for members of NOAH to post announcements of meetings and social events, and tell their success stories.
NOAH (New York Online Access to Health): Eyes and Low Vision
New York Online Access to Health. Links to sites about the eye especially selected for patients and the general public. En Español: los ojos y la visión
North American Neuro-Ophthalmology Society (NANOS)
Professional Society information for members as well as some patient informational brochures on such topics as migraines, myasthenia gravis, pseudotumor cerebri, and thyoid eye disease.
North Carolina Society of Eye Physicians and Surgeons
Has an extensive links page and NC legislative section.
North Dakota Society of Eye Physicians and Surgeons
Does not have a web site as of April 2006
Northern Rockies Optometric Conference
Has annual meeting information; patient education information; and a doctor's search.
The Nova Scotia Association of Optometrists
Has search engine for NS optometrists. Has eye information.
Nystagmus Network
Information about nystagmus.
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Ocular Heritage Society
For members who appreciate, conserve and collect items relating to the ophthalmic sciences. Has information on French spectacles from 1800.
Ocular Motor Apraxia
Written for the layperson concerned about OMA.Support groups, mailing list, message board, a bibliography about OMA.
Ocular Microbiology and Immunology Group (OMIG
Contact information, OMIG meetings, and helpful links for members.
Ocularists Association of Australia
The Ocularists Association of Australia was founded as a way to ensure a high standard of service and care for artificial eye recipients in Australia. Includes a mission statement and code of ethics. Standards are under development. Some support groups are listed.
Ohio Ophthalmological Society
About the organization, membership and legislation. Also community resources, practice management, educational opportunities and related links.
Oklahoma Academy of Ophthalmology
Oklahoma ophthalmologist directory. Has legislative information and some internet links.
Ontario Association of Optometrists
Has an optometry search engine and eye information.
Ophthalmic Photographers' Society
Besides having information about OPS, this sites contains helpful information about Ophthalmic photography, abundant images, Chapters about types of ophthalmic imaging and what it can reveal.
Optical Laboratories Association
An international business association founded in 1894 to serve the needs of the optical laboratory industry. OLA produces a variety of education and training materials for optical laboratories and eyecare professionals and it sponsors and administers the ANSI Z80 Committee and serves as the ANSI Z80 Secretariat.
The Optical Society of America
The mission of OSA is to promote the generation, application and archiving of knowledge in optics and photonics and to disseminate this knowledge worldwide.
The Opticians Association of America
Opticians Association of America general information, membership information, optician forum, information about continuing education, web site announcements.
The Opticians Association of Canada
Has sections for professional opticians, student opticians and the consumer.
Optometric Extension Program Foundation
The OEP is an international, non-profit organization dedicated to the gathering and dissemination of information on Vision.
Optometric Historical Society
An organization for persons interested in the history of optometry, spectacle lenses, vision science, or related topics.
Optometric Physicians of Washington
Has eye health information and an optometric physician's search engine.
ORBIS International
About the organization. ORBIS is a nonprofit, humanitarian organization dedicated to preserving and restoring sight in the developing world. Through innovative programs and partnerships, ORBIS produces long-term, sustainable solutions to preventable blindness that emphasize training of medical personnel, strengthening of in-country eye care institutions, and expanding delivery of quality eye care and prevention strategies in those parts of the world where the need is greatest.
Oregon Academy of Ophthalmology
About the academy, educational opportunities and the way of serving three audiences: public, members and other Ophthalmologists. Includes a search engine to find ophthalmologists.
Oregon Optometric Physicians Association
Has eye health information and an optometric physician's search engine.
Orthokeratology Academy of America
Has online version of The Corrected View, its journal. Serves orthokeratologists around the world. Has some consumer links and a professional membership page.
Orthoptic Association of Australia, Inc. (OAA)
About Orthoptics, the association and conferences offered through OAA.
Orthoptics Online
American Association of Certified Orthoptics and The American Orthoptic Council website with Continuting Opportunities, training programs, the American Orthoptic Journal and more.
Outpatient Ophthalmic Surgery Society
Providing education, information, and advocacy with government agencies for its members and their ASCs. Helping ASC owners and ophthalmic surgeons utilizing ASCs provide high quality, cost-effective surgical care.
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Pan-American Association of Ophthalmology
Non-profit organization whose mission is the continuing education of ophthalmologists, the prevention of blindness, and the promotion of scientific and cultural exchange among ophthalmologists in the Western Hemisphere and the world.
Pediatric Keratoplasty Association
An association dedicated to the study of Pediatric Keratoplasty. Site includes Physician and eye information areas, research information, newsletters, meeting information for physicians and an interactive web board.
Pennsylvania Academy of Ophthalmology
An association of "Eye MDs". Some eye information. Calendar of events. Internet links to ophthalmic groups.
Prevent Blindness America
National voluntary health agency working to prevent blindness. The site contains Eye Facts and Fun, including Eye Health and Safety Tips, Glaucoma Information, and the Effects of Computers on Your Eyes.
Prince Edward Island Association of Optometrists
Has an eye doctor search engine; information on eye safety and eye health.
Puerto Rico Ophthalmological Society
Web site in Spanish language. Directory search for ophthalmologist. Some eye information.
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-Q-
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-R-
Retina Australia
Retina Australia, Inc., formerly The Retinitis Pigmentosa Society (RP Society), represents people who live with retinitis pigmentosa and other retinal dystrophies. These are degenerative diseases causing low vision and a gradual deterioration of a person's sight. The work of RA Inc. is carried out predominantly by volunteers, many who are vision impaired and know the implications of vision loss. Retina Australia is committed to raising funds to support research into treatments and a cure for RP and all other retinal dystrophies.
Retina International
Retina International (formerly known as the International Retinitis Pigmentosa Assoc. - IRPA) is a voluntary charitable umbrella association of 34 national societies each of which is formed by people with Retinitis pigmentosa (RP), Usher Syndrome, Macular Degeneration and allied retinal dystrophies, their families and friends.
Retina Society
Has a directory of members. Sponsors an annual meeting.
Rhode Island Society of Eye Physicians and Surgeons
Does not have a web site as of April 2006
ROPARD: Association for Retinopathy of Prematurity and Related Retinal Diseases
About ROP, information and links for parents, videos, and a newsletter.
Royal National Institute for the Blind , UK
London based Royal National Institute for the Blind. UK’s leading charity offering information, support and advice to over two million people with sight problems. Helps anyone with a sight problem – not just with braille, Talking Books and computer training, but with imaginative and practical solutions to everyday challenges. Funds pioneering research into preventing and treating eye disease.
Royal Victorian Institute for the Blind
RVIB, Melbourne, Australia. RVIB has been providing services, resources and support to Victorians who are blind or vision impaired so that they may lead full and independent lives.
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-S-
Saskatchewan Association Of Optometrists
Association of Optometrists providing eyecare. Has an optometrist search engine and eye information
SIDUO
Societas Internationalis Pro Diagnostica Ultrasonica in Ophthalmologia, International Ophthalmic Echography Organization
Sjogren's Syndrome Foundation, Inc.
The Foundation provides patients practical information and coping strategies that minimize the effects of Sjögren's syndrome. In addition, the Foundation is the clearinghouse for medical information and is the recognized national advocate for Sjögren's syndrome.
SNOF: Syndicat National des Ophtalmologistes de France
Especially see the photothèque.
Sociedad Colombiana de Oftalmologia
The Society of ophthalmologists from Colombia, South America. Their purpose is to aid the development of scientific aspects of ophthalmology. It includes a vision science journal list, information on practice patterns. The website is in Spanish.
Societas Internationalis Pro Diagnostica Ultrasonica in Ophthalmologia: See SIDUO
Society of Military Ophthalmologists
A society for active duty and former or retired ophthalmologists of the U. S. Army, Air Force, Navy, and Public Health Service with some helpful links.
South Carolina Society of Ophthalmology
South Carolina's Eye MDs. The activities of this society and some internet links.
Southern Council of Optometrists
SoCO is comprised of the state associations of the following states: Alabama, Arkansas, Florida, Georgia, Kentucky, Louisiana, Mississippi, North Carolina, South Carolina, Tennessee, Virginia and West Virginia. The corporation name is SECO International.
South Dakota Academy of Ophthalmology
Does not have a web site as of April 2006
SPIE: International Society for Optical Engineering
SPIE is a not-for-profit society that has become the largest international force for the exchange, collection and dissemination of knowledge in optics, photonics and imaging.
Surgical Eye Expeditions (S.E.E.) International
Surgical Eye Expeditions (SEE) International, Inc. is a non-profit humanitarian organization that provides medical, surgical and educational services by volunteer ophthalmic surgeons with the primary objective of restoring sight to disadvantaged blind individuals worldwide.
Surgical Eyes Foundation
Surgical Eyes™ is an organization founded by people with longer-term complications from refractive surgery to assist others who have had unsuccessful LASIK, LASEK, PRK, RK, AK, ALK or other elective refractive surgeries. We help identify current remedies and spur development of future technologies to help us overcome our surgically created visual difficulties...
Swiss Orthoptics SVO/ASO
Syndicat National des Ophtalmologistes de France
Phototheque, Annonces, Conges, Art, Histoire, Liens.
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Talking Newspaper Association, UK
for people with Low Vision.
Tear Film & Ocular Surface Society
Purpose is to advance the research, literacy & educational aspects of the scientific field of the tearfilm and ocular surface.
Tennessee Academy of Ophthalmology
About the Academy, their education and the provided resources of assistance. Includes an ophthalmologist search engine.
Texas Ophthalmological Association
Online search directory for ophthalmologists. Includes legislative information.
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Unite for Sight
A nonprofit organization that empowers communities worldwide to improve eye health and eliminate preventable blindness.
Utah Ophthalmological Society
Provides public information as well as updates members and other ophthalmic professionals on current news and educational opportunities. Online Directory of members.
Utah Optometric Association
Has a doctor locator. Has a market place and calendar of events.
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Verband der Spezialkliniken Deutschlands für Augenlaser und Refraktive Chirurgie e.V.
Der Verband der Spezialkliniken Deutschlands fuer Augenlaser und Refraktive Chirurgie e.V. (VSDAR) hat es sich zum Ziel gesetzt, umfassend ueber die operativen Methoden zur Korrektur der Fehlsichtigkeiten zu informieren und aufzuklaeren. Ausserdem unterstuetzt er seine Mitglieder bei der Qualitaetssicherung sowie der Weiterentwicklung der eingesetzten Verfahren.
[German Language. The Association of German Clinics for Eye Laser and Refractive Surgery (VSDAR) attempts to educate and inform patients about the opportunities of operative vision correction. Furthermore, the association supports its members in quality assurance issues and the further development of the treatment.]
Vermont Ophthalmological Society
Does not have a web site as of April 2006
Virginia Society of Ophthalmology
Nonprofit organization committed to heightening public awareness that eye disease and blindness can be reduced through prevention, and early detection and treatment. Online Newsletter. Some internet links.
Vision Council of America / Better Vision Institute
VCA is the largest nonprofit trade association that represents the interests of the entire optical community. Members of VCA are those which sell optical products in North America and exhibit at International Vision Expo East, International Vision Expo West, and EyeQuest. VCA has four categories of membership. Full Membership, Associate Membership, Exhibitor Membership and Trade Media Membership.
Vision of Children
One of the organization's goals is to disseminate information about the detection, incidence, and treatment of diseases or conditions that either severely impair vision or cause total blindness in children. The site addresses ocular albinism and other hereditary diseases affecting the eye.
Volunteer Optometric Services to Humanity: See VOSH International
VOSH International
Provides vision care worldwide to people who can neither afford nor obtain such care. Newsletter available.
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Washington Academy of Eye Physicians and Surgeons
Ophthalmologist search engine. Medem eye health library link. Includes meeting information.
Washington DC Metropolitan Ophthalmological Society
Has search engine for DC ophthalmologists. Helpful websites for the public.
West Virginia Academy of Ophthalmology
About WVAO, their events and education with some featured links.
Wisconsin Academy of Ophthalmology
Does not have a web site as of April 2006
Women in Ophthalmology
About this organization, it's goals and a listing of their events through 2004.
World Council of Optometry
The World Council of Optometry (WCO) is an international organization dedicated to the enhancement and development of eye and vision care worldwide. Representing over 50 countries, WCO serves as a forum for member organizations to respond to public health needs and opportunities around the world.
Wyoming Ophthalmological Society
Does not have a web site as of April 2006
Wyoming Optometric Association
Has patient eye information and a doctor's search.
FAQ on EyE CARE
Why Does My Eye Twitch?
Mild twitching of the eyelid is a common phenomenon. Although these involuntary contractions of muscles are annoying, they are almost always temporary and completely harmless. The medical name for this kind of twitching is ocular myokymia. It is quite common and most often associated with fatigue. When your eye is twitching, it is not visible to anyone else. Ophthalmologists often are asked what causes the twitching and what can be done to stop it. Lack of sleep, too much caffeine or increased stress seem to be root causes. Often, gently massaging your eye will relieve the symptoms. Usually, the twitch will disappear after catching up on your sleep.
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General Vision
What is the difference between an ophthalmologist, an optometrist and an optician?
* An Ophthalmologist (MD) has a medical degree and is licensed to practice medicine and perform eye surgery.
* An ophthalmologist has had at least 12 years of education and training beyond high school and is qualified to diagnose and treat all eye diseases; perform surgery; prescribe and fit glasses and contact lenses.
* An Optometrist (OD) has a degree in optometry and is licensed to practice optometry. An optometrist has had at least six years of education and training beyond high school and is qualified to determine the need for glasses and contact lenses; prescribe optical correction; and screen for some eye conditions.
* An Optician usually has a combination of college (or two years of opticianry school) and on-the-job training. An optician is trained to fit and dispense eyeglasses or contact lenses based upon a prescription from a licensed ophthalmologist or optometrist.
How does normal vision develop?
Newborn infants are able to see, but as they use their eyes during the first months of life, vision improves. During early childhood years, the visual system changes quickly and vision continues to develop. If a child cannot use his or her eyes normally, vision does not develop properly and may even decrease. After the first nine years of life, the visual system is usually fully developed and usually cannot be changed.
The development of equal vision in both eyes is necessary for normal vision. Many occupations are not open to people who have good vision in one eye only. If the vision in one eye should be lost later in life from an accident or illness, it is essential that the other eye have normal vision. Without normal vision in at least one eye, a person is visually impaired.
How does the eye work?
When you take a picture, the lens in the front of the camera allows light through and focuses that light on the film that covers the back inside wall of the camera. When the light hits the film, a picture is taken. The eye works in much the same way. The front parts of the eye (the cornea, pupil and lens) are clear and allow light to pass through. The light also passes through the large space in the center of the eye called the vitreous cavity. The vitreous cavity is filled with a clear, jelly-like substance called the vitreous or vitreous gel. The light is focused by the cornea and the lens onto a thin layer of tissue called the retina, which covers the back inside wall of the eye. The retina is like the film in a camera. It is the seeing tissue of the eye. When the focused light hits the retina, a picture is taken. Messages about this picture are sent to the brain through the optic nerve. This is how we see.
Further information on this topic, visit anatomy of the eye.
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Eye Examinations
When should my child's eyes be examined?
Most physicians test vision as part of a child's medical examination. They may refer a child to an ophthalmologist (a medical eye doctor) if there is any sign of an eye condition. The American Academy of Ophthalmology and the American Academy of Pediatrics recommend the first vision screening occur in the hospital as part of a newborn baby's discharge examination. Visual function (including ocular alignment, etc.) also should be checked by the pediatrician or family physician during routine well-child exams (typically at two, four and six months of age). Later amblyopia and alignment screenings should take place at three years of age and then yearly after school age.
If you suspect your child suffers from decreased vision - amblyopia (poor vision in an otherwise normal appearing eye), refractive error (nearsightedness or farsightedness) or strabismus (misalignment of the eye in any direction) - or if there are hereditary factors that might predispose your child to eye disease, please make an appointment with an ophthalmologist as soon as possible. New techniques make it possible to test vision in infants and young children. If there is a family history of misaligned eyes, childhood cataracts or a serious eye disease, an ophthalmologist can begin checking your child's vision at a very early age.
When should an adult's eyes be examined?
Adult examinations of the eyes should be performed on a regular basis.
o Young adults (ages 20 - 39) should have their eyes examined every three-five years.
o Adults ages (ages 40 - 64) should have their eyes examined every two-four years.
o Seniors (over 65 years of age) should have their eyes examined every one-two years.
High risk adults include:
o People with diabetes
o People with glaucoma or strong family history of glaucoma
o People with AIDS/HIV
For more information about this topic, visit eye exams
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Visual Acuity, Vision Impairments and Low Vision
What are the medical terms for nearsightedness and farsightedness?
* The medical term for nearsightedness is myopia, correctable with glasses, contact lenses or, in some cases, refractive surgery (LASIK or Corneal Ring Implants).
* The medical term for farsightedness is hyperopia, correctable with glasses, contact lenses or, in some cases, refractive surgery.
* Related conditions (also correctable with glasses or contact lenses) include astigmatism and presbyopia.
What is visual acuity?
Acuity is the measure of the eye's ability to distinguish the smallest identifiable letter or symbol, its details and shape, usually at a distance of 20 feet. This measurement is usually given in a fraction. The top number refers to the testing distance measured in feet and the bottom number is the distance from which a normal eye should see the letter or shape. So, perfect vision is 20/20. If your vision is 20/60, that means what you can see at a distance of 20 feet, someone with perfect vision can see at a distance of 60 feet.
What is legal blindness?
You are legally blind when the best corrected central acuity is less than 20/200 (perfect visual acuity is 20/20) in your better eye, or your side vision is narrowed to 20 degrees or less in your better eye. Even if you are legally blind, you may still have some useful vision. If you are legally blind, you may qualify for certain government benefits.
What is visual impairment?
If neither of your eyes can see better than 20/60 without improvement from glasses or contacts, you may be defined as visually impaired. In addition, poor night vision, limited side vision, double vision and loss of vision in one eye may also determine visual impairment.
What is low vision?
Low vision is a term describing a level of vision below normal (20/70 or worse) that cannot be corrected with conventional glasses. Low vision is not the same as blindness. People with low vision can use their sight. However, low vision may interfere with the performance of daily activities, such as reading or driving.
Can eyes be transplanted?
No. Currently, there is no way to transplant a whole eye. However, corneas have been successfully transplanted for many years.
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Genetic Research
What is human genetic research?
The basis for many, if not most, diseases can be found in our genes. Genes and their protein products determine how we look and develop, how efficiently we process foods, how effectively we detoxify poisons and how vigorously we respond to infections. It is thought that more than 4,000 diseases arise from changed or mutated genes that are inherited from one's mother and/or father. Common disorders such as age-related macular degeneration, diabetes, heart disease and most cancers arise from a complex communication between multiple genes and between genes and factors in our environment. Genetic research studies are aimed at identifying these genes and understanding how changes in these genes lead to disease.
The benefits of human genetic research include medical breakthroughs made possible because of the combined commitment of participants and researchers. Identifying a gene opens many new diagnostic and treatment possibilities including earlier diagnosis of inherited eye diseases. Researchers also work to determine exactly what causes a particular eye disease and why the same disease does not effect everyone in the same way. As a result, researchers hope to develop improved treatment for specific eye diseases such as glaucoma and inherited retinal diseases including AMD. These discoveries will lead to improved eye care for future patients.
What is genetic testing?
Genetic tests, also called DNA-based tests, are some of the newest and most sophisticated techniques that we can use to test for genetic diseases. Most tests involve looking directly at the DNA in a specific disease-associated gene. The actual information of each gene is carried within the DNA itself. The DNA can be taken from cells in a sample of blood or, occasionally, from other body fluids or tissues.
The UM Kellogg Eye Center offers state-of-the-art genetic testing services through its Ophthalmic Molecular Diagnostic Laboratory. Testing allows ophthalmologists to confirm diagnoses and help patients understand their risks for certain inherited eye diseases. Kellogg is unique in its ability to offer this genetic testing service, which also provides patients with an exceptional genetic counseling program.
Are genetic study participants all patients at Kellogg?
Not necessarily. Enrollment involves donating a blood sample one time only and providing medical and family history information. This can all be done long distance. There is no cost to the participant.
What is genetic counseling?
Genetic counseling is a communication process which deals with the human problems associated with the occurrence, or the risk of occurrence, of a genetic disorder or birth defect in a family. As part of this process, the patient obtains information regarding diagnosis, treatment, prognosis and inheritance of the genetic condition or birth defect of concern to the family. In some cases genetic testing is available for specific genetic diseases.
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Contact Lenses
Can my child wear contact lenses during sports activities?
Yes, contact lenses provide excellent vision for most sports. However, they do not protect the eyes from injury. Therefore, contact lens wearers should use polycarbonate sports safety goggles or glasses when participating in sports. Also see information about preventing eye injuries.
Do contact lenses prevent nearsightedness (myopia) from getting worse?
No, there is no evidence that wearing contact lenses improves vision or prevents myopia from getting worse. Also see information about contact lenses.
Can I use my eyeglass prescription to buy over-the-counter contact lenses?
No, because it does not provide the specifications for lens diameter, thickness and base curve. A new prescription must be carefully fitted by an eye care specialist to avoid serious adverse reactions.
Is it safe for me to clean my contact lenses with a homemade solution?
Using commercial saline solutions is the safest method of cleaning lenses. Some studies have shown that homemade solutions may lead to corneal infections. Also see information about contact lenses.
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Computers, TVs, Lighting and Glasses
Will working at a computer screen hurt my eyes?
No, there is no evidence that working at a computer damages the eyes. However, long hours of work can be fatiguing to the eyes, neck and back. Monitor glare from various light sources can also be a problem. It is often helpful to take periodic breaks, looking off in the distance and adjusting your work station (angle of the monitor, height of the chair, changing the lighting, etc.).
Is pink-eye contagious?
Yes, viral conjunctivitis (pink-eye) is very common and is extremely contagious. Avoid touching eyes with your hands, wash hands frequently, do not share towels, and avoid work, school or daycare activities for a least five days or as long as discharge is present.
Will sitting too close to the television set hurt my child's eyes?
No, there is no scientific evidence that TV sets emit rays that are harmful to the eyes.
Why have I gradually found it harder to read without glasses?
The ability to focus on near objects decreases steadily with age and is referred to as presbyopia. Presbyopia is a natural aging of the lens. It is usually near the age of 40, when glasses or bifocals are prescribed to correct this condition.
Are sunglasses good for my eyes?
There is a benefit to wearing UV protective lenses--wearing them may protect against cataract formation. Clear lenses with UV protection may offer greater protection than dark lenses because they allow the eyes to be exposed to more light. This causes greater constriction of the pupil which lets less light enter the eyes.
Is my child likely to inherit my need for glasses?
Possibly. If both the biological parents wear glasses, your children are likely to need them as well.
Will reading in dim light hurt my eyes?
No, but most people are more comfortable reading with proper lighting which is bright enough to provide good illumination but not so bright as to cause glare.
How often do I need to get my prescription changed?
There is no predetermined schedule for changing glasses or contacts. It is necessary to change your prescription only when it no longer provide adequate correction. However, it is still a good idea to have regular eye examinations.
What materials are available for glasses?
Some of the newest materials for frames include titanium (virtually indestructible) and polycarbonate materials (recommended for high impact sports). Lenses are also made from polycarbonate materials, other types of light weight plastics and glass. Coatings include UV protection (recommended for all types of lenses), scratch-resistant protection, polarization, anti-glare and others. See the Kellogg Optical Shop for more information about glasses.
-1.1: What is Myopia ?
Myopia is often referred to as short-sightedness or near-sighted. ...
-1.2 What is Hyperopia ?
Hyperopia is often referred to as long-sightedness or far-sighted....
-1.3 What is Emmetropia ?
Emmetropia is just another name for an eye that has no optical defects and ...
-1.4 What is Astigmatism ?
An astigmatic eye generally has two different meridians, at 90degrees to ...
-1.5 What is Presbyopia ?
Presbyopia describes the condition whereby the amplitude of accommodation, ...
-1.6 How is Visual Acuity Measured
Visual acuity is the measure of the sensitivity of the visual system. ...
-2.0 Terminology of Spectacles
Lenses commonly used for spectacles are either spherical powered ...
-2.1 How to read a glasses prescription
A prescription for spectacles will generally contain the powers for lenses ...
-2.2 Why the difference between the way Optometrists and Ophthalmologists write the prescription ?
There are two ways of writing the prescription; referred to as plus-cyl ...
-2.3 How to convert between the two forms
To convert from plus-cyl form to minus-cyl form use the following steps:...
-2.4 Eyeglass Lens materials
Spectacle lenses are made of two main types of materials - plastic or glass....
-2.5 Types of Spectacle Lenses
+ Single Vision ...
-2.6 Ultra Violet absorption and Lenses
Spectacle lenses, depending on the type of material will absorb varying ...
-2.7 Standards Requirements for Spectacle Lenses
International and local standards define the properties of lenses that ...
-2.8 Cost of frames
Varies depending on the type of material, eg plastic frame to titanium metal....
-2.9 Cost of lenses
Like frames varies with the type of the material. Also depends if the ...
-2.10 Reducing the edge thickness of the lens
Since edge thickness is a function of lens power, centre thickness ...
-2.11 Internet Ordering of Prescriptions and Sunglasses
The are a wide variety of companies that advertise on the internet ...
-3.0 WWW Sites on Contact Lenses
URL: http: //www.sna.com/etonline/...
-3.1 Difference between soft and hard contact lenses
Soft lenses are manufactured from a plastic hydrogel polymer, ...
-3.2 How to Read a Contact Lens Description:
-3.2 Types of Soft Contact Lenses
Soft contact lenses vary depending on either the refractive correction that ...
-3.2.1 Spherical
Single prescription power 360 degrees around the lens....
-3.2.2 Toric
Contains both a spherical and cylinder component to correct prescriptions ...
-3.2.3 Disposable
Spherical or toric contact lenses which are designed to be worn for a ...
-3.2.4 Extended Wear
Lens manufactured from a high-water content material and/or with a very ...
-3.2.5 Bifocal Lenses
There are a variety of designs in bifocals, essentially all ...
-3.3 Types of Rigid Contact Lenses
Rigid contact lenses also vary depending on the material and the design of ...
-3.3.1 PMMA
Original material used in the construction of hard contact lenses....
-3.3.2 RGP
Combination of PMMA and other polymers to increase the oxygen permeability ...
-3.3.3 Spherical
same as for soft contact ...
-3.3.4 Toric
Can be either toric periphery, which is used for fitting reasons, ...
-3.3.5 Bifocal
The different types include;...
-3.4 Costs of Contact Lenses
Varies depending on the type of contact ...
-3.5 Solutions required for CL maintenance
In general all contact lenses, whether soft of rigid type, will ...
-3.6.1 Why do I have to clean my Contact Lenses ?
Cleaning removes surface debris and bacteria that may adhere to the ...
-3.6.2 Why is there a limit to the length of wearing time ?
The cornea the clear part of the eye, is avascular or without a blood supply....
-3.6.3 Can I lose the lens behind my eye ?
Short answer is no. The conjunctiva, the tissue that covers the white ...
-3.6.4 How do I tell if I've lost the lens from my eye?
Cover the other eye to determine if vision is still clear from the eye where ...
-3.6.5 How can I tell if I've put them in the wrong eye ?
Check the vision of each eye by covering alternate eyes with your hand....
-3.6.6 How to tell if the lenses are inside out ?
Soft lenses will appear as a smooth dish shape when placed on the end of ...
-3.6.7 How do I know when to dispose of my disposable lenses ?
The lenses will not automatically self-destruct at the end of the wearing ...
-3.6.8 Can I store my lenses in tap water ?
Short answer - No !. There are a number of nasty micro- organisms,...
-3.6.9 Can I store my lenses dry ?
Soft lenses - definitely not !. Soft lenses stored dry will turn into ...
-3.6.10 How long does it take to adapt to new lenses ?
Soft lenses are generally worn for 2-4hrs on the first day and the wearing ...
-3.6.11 Why do I have to use protein cleaner ?
Contact lenses are exposed to a complex environment whilst on the eye. ...
-3.6.12 Can I use eyedrops with my contact lenses ?
In general eyedrops shouldn't be used with contact lenses because the lens ...
-3.6.13 How do I get around dryness with contact lenses ?
Try using an in-eye lubricant. There can be some dryness if you work in ...
-3.7 Risks and Benefits of Contact Lenses
-3.8 Mail order contact lenses
Easiest method to locate the contact lens suppliers on the internet ...
-3.9 Making your own saline - risks
Greatest risk in manufacturing your own saline is the acanthamoeba. ...
-4.1 Introduction
This section, and the subsequent section, are only an overview of some ...
-4.2 Conjunctivitis
Conjunctivitis is an inflammation of a mucous membrane and therefore in ...
-4.3 Dry Eyes
- Causes [Details to be added ]...
-4.4 Eyelid Problems
Styes are common eyelid problems and are a type of boil involving an ...
-4.5 Keratoconus
Keratoconus (conical cornea) is an recessive inherited condition usually ...
-4.6 Herpes Zoster ("Shingles")
Affects the eye by encroaching from a skin lesion or starts ...
-4.7.1 General Effects of Radiation on the eye
UV radiation is classified ...
-4.7.2 Visual Displays and Radiation
-4.8 Iridology
This is postulated as a means of determining general health by ...
-5.1 Floaters and Spots in the Field of View
Floaters (muscae volitantes - flying flies) are spots before the eyes ...
-5.2 Macular Degeneration
The macular is the innermost part of the central retina; an area where ...
-5.3 Retinal Detachments
The retina is one of the three layers of the human eye. The innermost ...
-5.4 Diabetes and The Retina
Diabetes causes a number of retinal changes which can include haemorrhages,...
-5.5 Retinitis Pigmentosa
Retinitis Pigmentosa is a degeneration of the retinal pigment epithelium....
-5.6 Glaucoma
Glaucoma is a symptomatic condition and not a disease sui generis. It ...
-5.7 Cataracts
Cataracts are opacifications of the crystalline lens of the eye, causing ...
-5.8 Uveitis:
[ TBD - details to be added ]...
-5.9 Ocular Migraines:
-5.9.1 Introduction:
The following is an attempt to give an_introduction_only to this vast ...
-5.9.2 Classification of migraine:
I. Common migraine. The comprises about 80% of those with migraines. It is ...
-5.10 Chorioditis:
Choroiditis is an inflammation of the choroid, the second coat of ...
-6.1 Strabismus (Turned Eye)
A squint or strabismus is a failure of the two eyes to look at the same ...
-6.2 Amblyopia ("Lazy Eye")
Amblyopia is defined by Schapero et al. as the condition of reduced ...
-6.3 Problem(s) When Wearing Glasses
- Reflections....
-6.4.1 Vision Therapy Introduction
Common problems that require vision therapy ...
-6.4.2 Vision Therapy: Bates Method
Vision therapy, especially people claiming improvement of vision ...
-7.1 Defective Colour Vision:
Defects in colour vision, often incorrectly referred to as colour ...
-7.2 Classification of Congenital Colour Vision Defects
-7.3 Classification of Acquired Colour Vision Defects
-7.4 WWW Resources on Colour
-8.0 WWW Resources on Refractive Surgery:
URL: http://www.eyenet.org/public/faq/refractive_surgery_faq....
-8.1 Types of Refractive Surgery
There are basically 4 main operations performed for correction of ...
-8.2 Description of the Procedures:
-8.2.1 Suitability for each procedure
-8.3 Comparison of RK, PRK and ALK and LASIK:
PRK: involves less than 5% the depth of the cornea, typically. ...
-8.4 Complications of the Procedures
PRK Side Effects -...
-8.6 Criteria for Suitability of Procedures
PRK: The following guidelines are suggested for those individuals suitable ...
-8.7 Personal Experiences of Refractive Surgery
The following information details the personal experiences that some ...
-8.7 Personal Experiences of Refractive Surgery #2
The following information is details of experiences of patients ...
-8.7 Personal Experiences of Refractive Surgery #3
The following information was kindly contributed by Dr Robert Maloney M....
-8.7 Personal Experiences of Refractive Surgery #4
ALK:
-8.7 Costs of Surgery:
-8.8 Further information on Procedures:
The supplement to volume 9 No. 2 (March - April 1993) of the Journal ...
-8.9 Location of Places Performing Surgery
URL: http://www-or.stanford.edu/~mob/...
-8.10 OrthoKeratology
Fitting RGP contact lenses to change shape of cornea....
-10.0 Internet Vision/Health Resources
A large number of resources specific for ophthalmology/optometry ...
-10.1 Guide to On-Line Medical Resources
An extensive list of Internet Medical resources are listed in the ...
-10.2 Images of Eye Conditions/Diseases
Images of retinal and eye conditions as GIF/TIFF files ...
-11.0 Mailing Lists
A number of mailing lists are located on the Internet which deal with ...
-11.1 RPList
-11.2 CVNet
This list deals with colour and vision research. ...
-11.3 ColorCat
This list deals with Color ...
-11.4 HMatrix
[ Details to be added ]...
-11.5 BlindFam
This list is for the discussion of all aspects of family life as affected ...
-11.6 BlindNews
This list deals with issues of the visually handicapped. ...
-11.7 MedNet
[ Details to be added ]...
-11.8 EyeMove
This list is for scientists and clinicians interested in all aspects of ...
-11.9 LiveEye
This list also deals with colour and vision research. ...
-11.9a National Marfan Foundation
-11.10 PupilNet
From the announcement page......
-11.11 Sjogren's Syndrome List (SS-List)
This list is for the discussion of sjogren's syndrome....
-11.12 Ophthalmic Photography and Imaging Mailing List (OPTIMAL)
This list is for the discussion of ophthalmic photography ...
-11.13 Ophthalmogenetics Mail List
This list is for the discussion of Ophthalmogenetics (genetics ...
-11.14 Myopia Research mailing List:
-12.0 World Wide Web (WWW)
Other related Web servers include :...
-13.0 Email for Optoms/Ophthals & Net Resources
Currently the national board for USA is on the internet ...
-13.1 Commercial Interests on the Net:
Mild twitching of the eyelid is a common phenomenon. Although these involuntary contractions of muscles are annoying, they are almost always temporary and completely harmless. The medical name for this kind of twitching is ocular myokymia. It is quite common and most often associated with fatigue. When your eye is twitching, it is not visible to anyone else. Ophthalmologists often are asked what causes the twitching and what can be done to stop it. Lack of sleep, too much caffeine or increased stress seem to be root causes. Often, gently massaging your eye will relieve the symptoms. Usually, the twitch will disappear after catching up on your sleep.
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General Vision
What is the difference between an ophthalmologist, an optometrist and an optician?
* An Ophthalmologist (MD) has a medical degree and is licensed to practice medicine and perform eye surgery.
* An ophthalmologist has had at least 12 years of education and training beyond high school and is qualified to diagnose and treat all eye diseases; perform surgery; prescribe and fit glasses and contact lenses.
* An Optometrist (OD) has a degree in optometry and is licensed to practice optometry. An optometrist has had at least six years of education and training beyond high school and is qualified to determine the need for glasses and contact lenses; prescribe optical correction; and screen for some eye conditions.
* An Optician usually has a combination of college (or two years of opticianry school) and on-the-job training. An optician is trained to fit and dispense eyeglasses or contact lenses based upon a prescription from a licensed ophthalmologist or optometrist.
How does normal vision develop?
Newborn infants are able to see, but as they use their eyes during the first months of life, vision improves. During early childhood years, the visual system changes quickly and vision continues to develop. If a child cannot use his or her eyes normally, vision does not develop properly and may even decrease. After the first nine years of life, the visual system is usually fully developed and usually cannot be changed.
The development of equal vision in both eyes is necessary for normal vision. Many occupations are not open to people who have good vision in one eye only. If the vision in one eye should be lost later in life from an accident or illness, it is essential that the other eye have normal vision. Without normal vision in at least one eye, a person is visually impaired.
How does the eye work?
When you take a picture, the lens in the front of the camera allows light through and focuses that light on the film that covers the back inside wall of the camera. When the light hits the film, a picture is taken. The eye works in much the same way. The front parts of the eye (the cornea, pupil and lens) are clear and allow light to pass through. The light also passes through the large space in the center of the eye called the vitreous cavity. The vitreous cavity is filled with a clear, jelly-like substance called the vitreous or vitreous gel. The light is focused by the cornea and the lens onto a thin layer of tissue called the retina, which covers the back inside wall of the eye. The retina is like the film in a camera. It is the seeing tissue of the eye. When the focused light hits the retina, a picture is taken. Messages about this picture are sent to the brain through the optic nerve. This is how we see.
Further information on this topic, visit anatomy of the eye.
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Eye Examinations
When should my child's eyes be examined?
Most physicians test vision as part of a child's medical examination. They may refer a child to an ophthalmologist (a medical eye doctor) if there is any sign of an eye condition. The American Academy of Ophthalmology and the American Academy of Pediatrics recommend the first vision screening occur in the hospital as part of a newborn baby's discharge examination. Visual function (including ocular alignment, etc.) also should be checked by the pediatrician or family physician during routine well-child exams (typically at two, four and six months of age). Later amblyopia and alignment screenings should take place at three years of age and then yearly after school age.
If you suspect your child suffers from decreased vision - amblyopia (poor vision in an otherwise normal appearing eye), refractive error (nearsightedness or farsightedness) or strabismus (misalignment of the eye in any direction) - or if there are hereditary factors that might predispose your child to eye disease, please make an appointment with an ophthalmologist as soon as possible. New techniques make it possible to test vision in infants and young children. If there is a family history of misaligned eyes, childhood cataracts or a serious eye disease, an ophthalmologist can begin checking your child's vision at a very early age.
When should an adult's eyes be examined?
Adult examinations of the eyes should be performed on a regular basis.
o Young adults (ages 20 - 39) should have their eyes examined every three-five years.
o Adults ages (ages 40 - 64) should have their eyes examined every two-four years.
o Seniors (over 65 years of age) should have their eyes examined every one-two years.
High risk adults include:
o People with diabetes
o People with glaucoma or strong family history of glaucoma
o People with AIDS/HIV
For more information about this topic, visit eye exams
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Visual Acuity, Vision Impairments and Low Vision
What are the medical terms for nearsightedness and farsightedness?
* The medical term for nearsightedness is myopia, correctable with glasses, contact lenses or, in some cases, refractive surgery (LASIK or Corneal Ring Implants).
* The medical term for farsightedness is hyperopia, correctable with glasses, contact lenses or, in some cases, refractive surgery.
* Related conditions (also correctable with glasses or contact lenses) include astigmatism and presbyopia.
What is visual acuity?
Acuity is the measure of the eye's ability to distinguish the smallest identifiable letter or symbol, its details and shape, usually at a distance of 20 feet. This measurement is usually given in a fraction. The top number refers to the testing distance measured in feet and the bottom number is the distance from which a normal eye should see the letter or shape. So, perfect vision is 20/20. If your vision is 20/60, that means what you can see at a distance of 20 feet, someone with perfect vision can see at a distance of 60 feet.
What is legal blindness?
You are legally blind when the best corrected central acuity is less than 20/200 (perfect visual acuity is 20/20) in your better eye, or your side vision is narrowed to 20 degrees or less in your better eye. Even if you are legally blind, you may still have some useful vision. If you are legally blind, you may qualify for certain government benefits.
What is visual impairment?
If neither of your eyes can see better than 20/60 without improvement from glasses or contacts, you may be defined as visually impaired. In addition, poor night vision, limited side vision, double vision and loss of vision in one eye may also determine visual impairment.
What is low vision?
Low vision is a term describing a level of vision below normal (20/70 or worse) that cannot be corrected with conventional glasses. Low vision is not the same as blindness. People with low vision can use their sight. However, low vision may interfere with the performance of daily activities, such as reading or driving.
Can eyes be transplanted?
No. Currently, there is no way to transplant a whole eye. However, corneas have been successfully transplanted for many years.
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Genetic Research
What is human genetic research?
The basis for many, if not most, diseases can be found in our genes. Genes and their protein products determine how we look and develop, how efficiently we process foods, how effectively we detoxify poisons and how vigorously we respond to infections. It is thought that more than 4,000 diseases arise from changed or mutated genes that are inherited from one's mother and/or father. Common disorders such as age-related macular degeneration, diabetes, heart disease and most cancers arise from a complex communication between multiple genes and between genes and factors in our environment. Genetic research studies are aimed at identifying these genes and understanding how changes in these genes lead to disease.
The benefits of human genetic research include medical breakthroughs made possible because of the combined commitment of participants and researchers. Identifying a gene opens many new diagnostic and treatment possibilities including earlier diagnosis of inherited eye diseases. Researchers also work to determine exactly what causes a particular eye disease and why the same disease does not effect everyone in the same way. As a result, researchers hope to develop improved treatment for specific eye diseases such as glaucoma and inherited retinal diseases including AMD. These discoveries will lead to improved eye care for future patients.
What is genetic testing?
Genetic tests, also called DNA-based tests, are some of the newest and most sophisticated techniques that we can use to test for genetic diseases. Most tests involve looking directly at the DNA in a specific disease-associated gene. The actual information of each gene is carried within the DNA itself. The DNA can be taken from cells in a sample of blood or, occasionally, from other body fluids or tissues.
The UM Kellogg Eye Center offers state-of-the-art genetic testing services through its Ophthalmic Molecular Diagnostic Laboratory. Testing allows ophthalmologists to confirm diagnoses and help patients understand their risks for certain inherited eye diseases. Kellogg is unique in its ability to offer this genetic testing service, which also provides patients with an exceptional genetic counseling program.
Are genetic study participants all patients at Kellogg?
Not necessarily. Enrollment involves donating a blood sample one time only and providing medical and family history information. This can all be done long distance. There is no cost to the participant.
What is genetic counseling?
Genetic counseling is a communication process which deals with the human problems associated with the occurrence, or the risk of occurrence, of a genetic disorder or birth defect in a family. As part of this process, the patient obtains information regarding diagnosis, treatment, prognosis and inheritance of the genetic condition or birth defect of concern to the family. In some cases genetic testing is available for specific genetic diseases.
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Contact Lenses
Can my child wear contact lenses during sports activities?
Yes, contact lenses provide excellent vision for most sports. However, they do not protect the eyes from injury. Therefore, contact lens wearers should use polycarbonate sports safety goggles or glasses when participating in sports. Also see information about preventing eye injuries.
Do contact lenses prevent nearsightedness (myopia) from getting worse?
No, there is no evidence that wearing contact lenses improves vision or prevents myopia from getting worse. Also see information about contact lenses.
Can I use my eyeglass prescription to buy over-the-counter contact lenses?
No, because it does not provide the specifications for lens diameter, thickness and base curve. A new prescription must be carefully fitted by an eye care specialist to avoid serious adverse reactions.
Is it safe for me to clean my contact lenses with a homemade solution?
Using commercial saline solutions is the safest method of cleaning lenses. Some studies have shown that homemade solutions may lead to corneal infections. Also see information about contact lenses.
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Computers, TVs, Lighting and Glasses
Will working at a computer screen hurt my eyes?
No, there is no evidence that working at a computer damages the eyes. However, long hours of work can be fatiguing to the eyes, neck and back. Monitor glare from various light sources can also be a problem. It is often helpful to take periodic breaks, looking off in the distance and adjusting your work station (angle of the monitor, height of the chair, changing the lighting, etc.).
Is pink-eye contagious?
Yes, viral conjunctivitis (pink-eye) is very common and is extremely contagious. Avoid touching eyes with your hands, wash hands frequently, do not share towels, and avoid work, school or daycare activities for a least five days or as long as discharge is present.
Will sitting too close to the television set hurt my child's eyes?
No, there is no scientific evidence that TV sets emit rays that are harmful to the eyes.
Why have I gradually found it harder to read without glasses?
The ability to focus on near objects decreases steadily with age and is referred to as presbyopia. Presbyopia is a natural aging of the lens. It is usually near the age of 40, when glasses or bifocals are prescribed to correct this condition.
Are sunglasses good for my eyes?
There is a benefit to wearing UV protective lenses--wearing them may protect against cataract formation. Clear lenses with UV protection may offer greater protection than dark lenses because they allow the eyes to be exposed to more light. This causes greater constriction of the pupil which lets less light enter the eyes.
Is my child likely to inherit my need for glasses?
Possibly. If both the biological parents wear glasses, your children are likely to need them as well.
Will reading in dim light hurt my eyes?
No, but most people are more comfortable reading with proper lighting which is bright enough to provide good illumination but not so bright as to cause glare.
How often do I need to get my prescription changed?
There is no predetermined schedule for changing glasses or contacts. It is necessary to change your prescription only when it no longer provide adequate correction. However, it is still a good idea to have regular eye examinations.
What materials are available for glasses?
Some of the newest materials for frames include titanium (virtually indestructible) and polycarbonate materials (recommended for high impact sports). Lenses are also made from polycarbonate materials, other types of light weight plastics and glass. Coatings include UV protection (recommended for all types of lenses), scratch-resistant protection, polarization, anti-glare and others. See the Kellogg Optical Shop for more information about glasses.
-1.1: What is Myopia ?
Myopia is often referred to as short-sightedness or near-sighted. ...
-1.2 What is Hyperopia ?
Hyperopia is often referred to as long-sightedness or far-sighted....
-1.3 What is Emmetropia ?
Emmetropia is just another name for an eye that has no optical defects and ...
-1.4 What is Astigmatism ?
An astigmatic eye generally has two different meridians, at 90degrees to ...
-1.5 What is Presbyopia ?
Presbyopia describes the condition whereby the amplitude of accommodation, ...
-1.6 How is Visual Acuity Measured
Visual acuity is the measure of the sensitivity of the visual system. ...
-2.0 Terminology of Spectacles
Lenses commonly used for spectacles are either spherical powered ...
-2.1 How to read a glasses prescription
A prescription for spectacles will generally contain the powers for lenses ...
-2.2 Why the difference between the way Optometrists and Ophthalmologists write the prescription ?
There are two ways of writing the prescription; referred to as plus-cyl ...
-2.3 How to convert between the two forms
To convert from plus-cyl form to minus-cyl form use the following steps:...
-2.4 Eyeglass Lens materials
Spectacle lenses are made of two main types of materials - plastic or glass....
-2.5 Types of Spectacle Lenses
+ Single Vision ...
-2.6 Ultra Violet absorption and Lenses
Spectacle lenses, depending on the type of material will absorb varying ...
-2.7 Standards Requirements for Spectacle Lenses
International and local standards define the properties of lenses that ...
-2.8 Cost of frames
Varies depending on the type of material, eg plastic frame to titanium metal....
-2.9 Cost of lenses
Like frames varies with the type of the material. Also depends if the ...
-2.10 Reducing the edge thickness of the lens
Since edge thickness is a function of lens power, centre thickness ...
-2.11 Internet Ordering of Prescriptions and Sunglasses
The are a wide variety of companies that advertise on the internet ...
-3.0 WWW Sites on Contact Lenses
URL: http: //www.sna.com/etonline/...
-3.1 Difference between soft and hard contact lenses
Soft lenses are manufactured from a plastic hydrogel polymer, ...
-3.2 How to Read a Contact Lens Description:
-3.2 Types of Soft Contact Lenses
Soft contact lenses vary depending on either the refractive correction that ...
-3.2.1 Spherical
Single prescription power 360 degrees around the lens....
-3.2.2 Toric
Contains both a spherical and cylinder component to correct prescriptions ...
-3.2.3 Disposable
Spherical or toric contact lenses which are designed to be worn for a ...
-3.2.4 Extended Wear
Lens manufactured from a high-water content material and/or with a very ...
-3.2.5 Bifocal Lenses
There are a variety of designs in bifocals, essentially all ...
-3.3 Types of Rigid Contact Lenses
Rigid contact lenses also vary depending on the material and the design of ...
-3.3.1 PMMA
Original material used in the construction of hard contact lenses....
-3.3.2 RGP
Combination of PMMA and other polymers to increase the oxygen permeability ...
-3.3.3 Spherical
same as for soft contact ...
-3.3.4 Toric
Can be either toric periphery, which is used for fitting reasons, ...
-3.3.5 Bifocal
The different types include;...
-3.4 Costs of Contact Lenses
Varies depending on the type of contact ...
-3.5 Solutions required for CL maintenance
In general all contact lenses, whether soft of rigid type, will ...
-3.6.1 Why do I have to clean my Contact Lenses ?
Cleaning removes surface debris and bacteria that may adhere to the ...
-3.6.2 Why is there a limit to the length of wearing time ?
The cornea the clear part of the eye, is avascular or without a blood supply....
-3.6.3 Can I lose the lens behind my eye ?
Short answer is no. The conjunctiva, the tissue that covers the white ...
-3.6.4 How do I tell if I've lost the lens from my eye?
Cover the other eye to determine if vision is still clear from the eye where ...
-3.6.5 How can I tell if I've put them in the wrong eye ?
Check the vision of each eye by covering alternate eyes with your hand....
-3.6.6 How to tell if the lenses are inside out ?
Soft lenses will appear as a smooth dish shape when placed on the end of ...
-3.6.7 How do I know when to dispose of my disposable lenses ?
The lenses will not automatically self-destruct at the end of the wearing ...
-3.6.8 Can I store my lenses in tap water ?
Short answer - No !. There are a number of nasty micro- organisms,...
-3.6.9 Can I store my lenses dry ?
Soft lenses - definitely not !. Soft lenses stored dry will turn into ...
-3.6.10 How long does it take to adapt to new lenses ?
Soft lenses are generally worn for 2-4hrs on the first day and the wearing ...
-3.6.11 Why do I have to use protein cleaner ?
Contact lenses are exposed to a complex environment whilst on the eye. ...
-3.6.12 Can I use eyedrops with my contact lenses ?
In general eyedrops shouldn't be used with contact lenses because the lens ...
-3.6.13 How do I get around dryness with contact lenses ?
Try using an in-eye lubricant. There can be some dryness if you work in ...
-3.7 Risks and Benefits of Contact Lenses
-3.8 Mail order contact lenses
Easiest method to locate the contact lens suppliers on the internet ...
-3.9 Making your own saline - risks
Greatest risk in manufacturing your own saline is the acanthamoeba. ...
-4.1 Introduction
This section, and the subsequent section, are only an overview of some ...
-4.2 Conjunctivitis
Conjunctivitis is an inflammation of a mucous membrane and therefore in ...
-4.3 Dry Eyes
- Causes [Details to be added ]...
-4.4 Eyelid Problems
Styes are common eyelid problems and are a type of boil involving an ...
-4.5 Keratoconus
Keratoconus (conical cornea) is an recessive inherited condition usually ...
-4.6 Herpes Zoster ("Shingles")
Affects the eye by encroaching from a skin lesion or starts ...
-4.7.1 General Effects of Radiation on the eye
UV radiation is classified ...
-4.7.2 Visual Displays and Radiation
-4.8 Iridology
This is postulated as a means of determining general health by ...
-5.1 Floaters and Spots in the Field of View
Floaters (muscae volitantes - flying flies) are spots before the eyes ...
-5.2 Macular Degeneration
The macular is the innermost part of the central retina; an area where ...
-5.3 Retinal Detachments
The retina is one of the three layers of the human eye. The innermost ...
-5.4 Diabetes and The Retina
Diabetes causes a number of retinal changes which can include haemorrhages,...
-5.5 Retinitis Pigmentosa
Retinitis Pigmentosa is a degeneration of the retinal pigment epithelium....
-5.6 Glaucoma
Glaucoma is a symptomatic condition and not a disease sui generis. It ...
-5.7 Cataracts
Cataracts are opacifications of the crystalline lens of the eye, causing ...
-5.8 Uveitis:
[ TBD - details to be added ]...
-5.9 Ocular Migraines:
-5.9.1 Introduction:
The following is an attempt to give an_introduction_only to this vast ...
-5.9.2 Classification of migraine:
I. Common migraine. The comprises about 80% of those with migraines. It is ...
-5.10 Chorioditis:
Choroiditis is an inflammation of the choroid, the second coat of ...
-6.1 Strabismus (Turned Eye)
A squint or strabismus is a failure of the two eyes to look at the same ...
-6.2 Amblyopia ("Lazy Eye")
Amblyopia is defined by Schapero et al. as the condition of reduced ...
-6.3 Problem(s) When Wearing Glasses
- Reflections....
-6.4.1 Vision Therapy Introduction
Common problems that require vision therapy ...
-6.4.2 Vision Therapy: Bates Method
Vision therapy, especially people claiming improvement of vision ...
-7.1 Defective Colour Vision:
Defects in colour vision, often incorrectly referred to as colour ...
-7.2 Classification of Congenital Colour Vision Defects
-7.3 Classification of Acquired Colour Vision Defects
-7.4 WWW Resources on Colour
-8.0 WWW Resources on Refractive Surgery:
URL: http://www.eyenet.org/public/faq/refractive_surgery_faq....
-8.1 Types of Refractive Surgery
There are basically 4 main operations performed for correction of ...
-8.2 Description of the Procedures:
-8.2.1 Suitability for each procedure
-8.3 Comparison of RK, PRK and ALK and LASIK:
PRK: involves less than 5% the depth of the cornea, typically. ...
-8.4 Complications of the Procedures
PRK Side Effects -...
-8.6 Criteria for Suitability of Procedures
PRK: The following guidelines are suggested for those individuals suitable ...
-8.7 Personal Experiences of Refractive Surgery
The following information details the personal experiences that some ...
-8.7 Personal Experiences of Refractive Surgery #2
The following information is details of experiences of patients ...
-8.7 Personal Experiences of Refractive Surgery #3
The following information was kindly contributed by Dr Robert Maloney M....
-8.7 Personal Experiences of Refractive Surgery #4
ALK:
-8.7 Costs of Surgery:
-8.8 Further information on Procedures:
The supplement to volume 9 No. 2 (March - April 1993) of the Journal ...
-8.9 Location of Places Performing Surgery
URL: http://www-or.stanford.edu/~mob/...
-8.10 OrthoKeratology
Fitting RGP contact lenses to change shape of cornea....
-10.0 Internet Vision/Health Resources
A large number of resources specific for ophthalmology/optometry ...
-10.1 Guide to On-Line Medical Resources
An extensive list of Internet Medical resources are listed in the ...
-10.2 Images of Eye Conditions/Diseases
Images of retinal and eye conditions as GIF/TIFF files ...
-11.0 Mailing Lists
A number of mailing lists are located on the Internet which deal with ...
-11.1 RPList
-11.2 CVNet
This list deals with colour and vision research. ...
-11.3 ColorCat
This list deals with Color ...
-11.4 HMatrix
[ Details to be added ]...
-11.5 BlindFam
This list is for the discussion of all aspects of family life as affected ...
-11.6 BlindNews
This list deals with issues of the visually handicapped. ...
-11.7 MedNet
[ Details to be added ]...
-11.8 EyeMove
This list is for scientists and clinicians interested in all aspects of ...
-11.9 LiveEye
This list also deals with colour and vision research. ...
-11.9a National Marfan Foundation
-11.10 PupilNet
From the announcement page......
-11.11 Sjogren's Syndrome List (SS-List)
This list is for the discussion of sjogren's syndrome....
-11.12 Ophthalmic Photography and Imaging Mailing List (OPTIMAL)
This list is for the discussion of ophthalmic photography ...
-11.13 Ophthalmogenetics Mail List
This list is for the discussion of Ophthalmogenetics (genetics ...
-11.14 Myopia Research mailing List:
-12.0 World Wide Web (WWW)
Other related Web servers include :...
-13.0 Email for Optoms/Ophthals & Net Resources
Currently the national board for USA is on the internet ...
-13.1 Commercial Interests on the Net:
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