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December 14, 2002

Vision Chip, The

From: New York Times - 14 Dec 2002


For the blind, there is a glint in the darkness: the possibility of artificial sight. For the first time, researchers are performing real-life tests of a surgical prosthetic implant designed to stimulate a damaged retina into producing images that are the equivalent of a miniature lighted-up scoreboard.

The newest technologies were inspired by cochlear implants for the deaf, and while the tests are only in the early stages, the potential could be just as revolutionary (and controversial). Last year, the California-based Second Sight received F.D.A. approval to test its devices on human subjects. Two volunteers suffering from severe retinal degeneration (but not blindness from birth) were surgically implanted with an array of electrodes and fitted with a pair of glasses mounted with a camera. The camera receives images and then wirelessly transmits this data to the implant, electrically stimulating the eye's failing retinal cells. From there, the data passes through the healthy optic nerve to the brain. The outcome resembles the grid in a TV screen: individual ''cells'' light up, forming a composite image.

Second Sight presented its findings at academic conferences earlier this year, and its work has been submitted for publication. Meanwhile, another group at Columbia is racing ahead with its own prosthesis. An Illinois-based company, Optobionics, is developing a similar mechanism using solar cells and has implanted the experimental version in six patients. And at the University of Utah, Richard Normann is working on an even more radical possibility: a brain implant, one that might potentially work on patients whose retinas or optic nerves are nonfunctional, or even those who lack eyes entirely.

So far, these implants are more rough drafts than bionic miracles. ''They don't provide anything close to normal vision,'' says Dr. Robert Greenberg, the C.E.O. of Second Sight. ''But patients can do tasks: identify a letter on the wall, count objects in front of them, locate objects in the room.'' But if full F.D.A. approval is years away, this move into real-life uses is tantalizing. According to Greenberg, all sorts of data could potentially be transmitted through the camera's lens, from ultraviolet light to X-ray vision. For many blind people, of course, any light at all would be welcome.

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