`Bionic' implant restores partial vision

James Randerson

San Francisco: Six visually challenged persons have had their sight partially restored by a "bionic eye" surgically implanted on to their retina.

Although it restores only very rudimentary vision, the device has proved so successful that its developers are about to begin a study of a more sophisticated version with between 50 and 75 patients.

If this trial goes to plan, the device could be available to patients in two years.

The bionic eye works by converting images from a tiny camera mounted on a pair of glasses into a grid of 16 electrical signals that transmit directly to the nerve endings in the retina.

Pocket device

The camera in the glasses sends a signal to a pocket device the size of a Blackberry which processes the images in real time into a grid of electrical signals. This is then beamed to the eye implant, which sends it directly to nerve endings in the retina.

In the current devices, the receiver for the signal is implanted under the skin behind the ear with a wire connection to the eye implant, but the team has shrunk the electronics so much that the improved version fits under the skin around the eye.

The implants will be most successful in patients who were once fully sighted rather than people who were without sight from birth.

Guardian Newspapers Limited 2006