Bionic eye helps the blind enter new dimensions of sight ...........

The American-made Argus implant ('bionic eye') restores partial vision to those blinded by retinitis pigmentosa. The second generation of the implant will hit the European market this summer.


Germany's national health care system has agreed to cover the Argus, and the United Kingdom and France are likely to follow. With a 100,000 US dollar (70,000 euro) price tag, whether or not the implant will be able to restore sight to tens of thousands of Europeans won't be determined by the success of the product, but by the ability of the manufacturer and medical community to convince other healthcare systems to pay for it

Officials are likely to have a hard time denying a blind person the chance of partially restoring their sight. Terry Byland from Los Angeles went blind in his forties. Standing outside the Riverside Braille Club, east of Los Angeles, he says: "The first time I touched that door with this cane I hit it right in the middle of the door each time. There was no guess work about where I was going."

Terry Byland is a member of the lively Riverside Braille Club. Most club members are well adjusted to life without sight. They gather on Tuesdays for exercise, bingo and choir practice. Before losing his sight, Terry sold machinery. Shortly after he was diagnosed with retinitis pigmentosa, his eyesight disappeared, leaving him scared and frustrated.

Eye works like a camera

In many ways, the eye operates like a camera. For those suffering from retinitis pigmentosa, like Terry, seeing becomes impossible because of deteriorating photoreceptors in the retina - the equivalent of having a layer of camera film missing. The light enters through the lens and illuminates the film or the retina and transmits the picture of the outside world to the brain.

The Argus, the artificial retina, communicates with the brain through electric impulses, just like a full functioning retina would. A small video camera attached to a pair of glasses sends its picture to a computer the size of a deck of cards in the user's pocket. The computer translates the image into electric impulses and wirelessly communicates the information to electrodes implanted on the back of the eye.

The result is a highly-pixelated black and white picture. "Describing what they see is very challenging. But what we can do is measure their performance on tasks," explains Brian Mech of Second Sight Medical Products in Los Angeles. He has been a leader on the Argus development team for over a decade. "They can tell if people are approaching or leaving, into what direction they are moving."

Enhanced features

Terry Byland was one of two patients to receive the first generation of the implant during the earliest of the clinical trails. His feedback allowed for the following version to be enhanced, and new features were added. "I'd give anything to have the new version, but the FDA won't allow that," says Byland.

The American FDA, or Food and Drug Administration, has yet to give the green light to the Argus, even though European health officials have already granted approval. The FDA is notoriously tough, but all in the name of safety. Others, particularly those holding the purse strings, have a different set of questions. For example, how much will the implant affect the lifestyles of those who receive it?

Terry Byland does not wear his glasses everywhere. For instance he points out, they don't work properly inside the Riverside Braille Club. "I've had them here before," he says, "and the contrast value here is lousy. What I mean by that is you walk in there and it is mostly all vanilla. There's not that much dark and light to work with. And without that the camera doesn't work that well."

People like Terry Byland who have been blind for a long time already have ways to compensate, like listening for the traffic of cars to stay in the lines of a pedestrian crossing. On the other hand, those who have recently lost their sight might not be so good at these new skills and may find the implant very useful.

Mind meets machine

The next generations of bionic eye might be different. The Argus II currently has 60 electrodes, but the team is hoping to develop that further eventually produce an implant with around two thousand electrodes. Adding electrodes is similar to adding pixels to a digital camera - more pixels means a better image.

Argus II glasses connected to a mini-computer

But there's a limit: "It turns out that God or nature is a much better engineer than man," warns Mech of Second Sight Medical Products, referring to the human eye. "At least when it comes to this part, because we could never build electrodes that are as efficient as our photodetectors."

While the Argus is an improvement, it has its technological limitations and is only applicable to a certain group of visually impaired. Since it's people with retinitis pigmentosa who are only approved to receive the device, Argus candidates make up a small fraction of those with advanced vision loss.

The real technological feat of this device is often overlooked, however. It's the first machine that interfaces directly with the brain to be made available to the public. So while possibilities of restoring sight may be limited, the possibilities of mind meets machine are something to look forward to.

Author: Annie Gilbertson
Editor: Guy Degen