Eye Camera May Help the Blind See

Nov. 22, 2002 -- Researchers at the University of Southern California have developed a form of artificial sight that has allowed two blind patients to know the difference between darkness and light, night and day.

Just that little bit of success holds some promise for restoring a degree of eyesight to as many as one million people who have lost sight to macular degeneration, or disease of the light-sensing cells of the retina, according to researchers at the University of Southern California's Doheny Retina Institute

Dr. Mark Humayun says the institute's researchers hope that the device under development will give back to blind patients the ability to do simple things.

"Pouring water into a cup, sitting at a table being able to see your plate, your fork and knife," Humayun said. "And then beyond that can they recognize maybe the facial features of their loved ones? Those are things we would like to get to."

Glasses With a Camera

The experimental device is made by a company called Second Sight in Santa Clarita, Calif. It now consists of a miniature camera attached to a pair of glasses that send a signal to a wireless receiver planted behind the patient's ear. The signal then goes through a tiny wire implanted under the skin, into the eye to an electronic chip attached to the retina itself.

That chip on the retina stimulates the optic nerve, giving the patient "vision."

Researchers have put electronic chips in the eyes of two blind patients. What they have been able to see so far is just sixteen pixels, 16 dots of light like light bulbs in a scoreboard.

Patients in the experiment are not able to recognize objects, but they can recognize changes in light. If scientists can increase the resolution to just 1,000 pixels, it would give blind people vision comparable to a poor television picture. Faces would become recognizable.

Leaning on the Brain

In a test simulating 1,000 pixels of vision, a person wearing the device is able to read large letters, recognize obstacles such as chairs and walls, and find their way down a corridor.

This artificial vision is designed for people who had sight and lost it. Their brains are accustomed to seeing, and even have the ability to fill in a sketchy picture.

"The brain is the ace that we hold in our hand because the human brain is an incredible computer that's able to use and get used to a very low input. So even with very few pixels and very few spots of light and maybe a third of them not even working, the brain can fill in the gaps and make use of a very crude image," Humayun said.

Ideally, the device would one day consists of a mini-camera installed in the eye itself, transmitting a signal to electronic chips on the retina. But there are a lot of problems to work out before that ever happens; how to power the device, and how to reliably attach to the chips to the retina, which has the consistency of wet tissue.

If current tests are successful, it will still be at least five years before the device is widely available.