Tiny 'digital camera' could restore vision to the blind

Published on 12/07/2006 00:40

THERE is fresh hope for hundreds of thousands of blind people that they may soon have their sight restored as researchers in Scotland are developing a prosthetic retina.

Using technology similar to that found in digital cameras, the tiny device would be implanted into the eye to stimulate a retina that was no longer working.

It is designed to help people with age-related macular degeneration and retinitis pigmentosa, conditions that affect about a million people in the UK. These conditions are caused by failure in the retina - the part of the eye which converts light into signals that are sent to the brain.

The micro-electronic device could translate light into electrical impulses, stimulating the retina and fooling the brain into believing the eye is still in working order.

"The device would contain an imaging detector with hundreds of pixels coupled to an array of microscopic stimulating electrodes," said Dr Keith Mathieson, who leads the team at Glasgow University developing the device.

"If light forms an image on the detector, then the result will be electrical stimulation of the retina in the shape of this image. The stimulated cells then send the information via the optic nerve to the brain.

"The imaging part of the system is based on the technology used in any digital camera."

The prototype of the implant has 100 pixels, but the researchers hope to increase this as their work progresses.

"Around 500 pixels would allow people to walk down the street and recognise faces," Dr Mathieson said.

The scientists say they are still five to ten years away from fitting the artificial retina to humans. If successful, however, the invention could transform the lives of up to a million people who have gone blind.

It is hoped that the tiny box, which would be about 5mm in diameter, would restore sufficient vision to allow people to go about their daily lives with greater ease.

So far the research team has carried out tests using animal retina cells cultured in the laboratory. Dr Mathieson said these tests had led the research team to believe that the device could restore sight in people. In the future, it may even be possible to incorporate a "smart chip" in the device, which would allow it to replay something the person had seen previously.

Dr Mathieson said that while this was certainly possible one day, it was still slightly in the realms of science fiction.

He said researchers were concentrating on trying to create a device that would restore useful vision.

"We are trying to get to the point where someone would no longer need a guide dog, rather than replicate perfect vision," Dr Mathieson said.

However, he added: "Beyond where we are today, it might be possible to make smart chips that have memory in them which would allow action replay and slow motion."

John Legg, director of the Royal National Institute of the Blind (RNIB) Scotland, welcomed the work of the scientists. "It will, however, be some years before this research bears fruit," he said.

"In the meantime, RNIB Scotland will continue to campaign to ensure that existing treatments are promptly and uniformly available to all who might benefit."