Sunday, April 15, 2007

New invention could give some sight to the blind

A tiny electronic device could allow people who've lost some of their vision to see again. The technology has already helped restore partial sight in blind people. Now scientists are building on that initial research.

Diseases that damage the retina are the primary cause of vision loss. For Hymen Marder, macular degeneration has left him with just a small amount of peripheral vision.

Hymen Marder, Visually Impaired: "There are times when I think I see something, but I really don't until I move my head to a certain point."

But researchers at USC's Doheny Eye Institute are working on a computerized eye implant to bypass the retina. It consists of a chip that's surgically implanted in the back of the eye. A small camera mounted on a pair of glasses transmits images to the chip, which sends the signals along the optic nerve to the patient's brain. An early version of the device helped patients with total vision loss see light. That version had only 16 electrodes. Now Dr. Mark Humayan is testing a new version with a 60 electrode chip.

Mark Humayun, M.D., Professor of Opthalmology: "We hope and we believe that the 60 electrode will allow much more detailed resolution, but it still probably will not allow someone to read or recognize faces."

Dr. Humayun's new version is four times smaller than the original, but can send even more visual information to the brain. The FDA has approved clinical trials for the device. Trials Dr. Humayan believes will help his team design even more powerful devices.

Mark Humayun, M.D.: "250, 300 or even 1000 electrodes - that's where we're headed. So we can get to the point of allowing the patients to read and recognize faces."

Meanwhile, Humayun hopes to have the current implant that restores partial vision on the market in two to three years. By the end of the year, the researchers will be testing the new implant in more than 50 people.


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