THE BIONIC EYE.(artificial retina for retinitis pigmentosa patients)

When Connie Schoeman was growing up, her family had a country house on a lake in New Hampshire, and she loved to sit outside at night and gaze at the stars. As an undergraduate at Pembroke College in the nineteen-forties, she studied medical technology, and when she moved to California in her twenties she worked at a hospital laboratory. Connie became an expert at identifying parasites and other pathogens in clinical specimens under the microscope. One afternoon, while she was driving, Connie was hit by a car that was backing out of a driveway. "I realized that I didn't see it from the corner of my eye," she told me. An ophthalmologist examined her. Although Connie's central vision was still sufficient for her to continue lab work, her retina was pocked by heavy coal-black deposits. Tests revealed that even with glasses her vision would be no better than 20/200, which meets the legal definition of blindness. She had experienced significant loss of her peripheral field and some loss of her central field. The ophthalmologist diagnosed retinitis pigmentosa, or R.P., an inherited disease in which the rods and cones of the retina degenerate. (The rods and cones convert light into electrical impulses, which are carried by the optic nerve to the brain, where images are formed.) Connie's eyes were otherwise healthy, but with the loss of the rods her peripheral vision and light perception faded, and with the loss of the cones her central vision and color perception atrophied. "Soon I couldn't see the stars," she said. "Then, after a few more years, I couldn't see the moon."

Retinitis pigmentosa occurs in approximately one in every four thousand people, and the disease usually becomes symptomatic in early adulthood. The condition, which grows worse over time, is incurable. When Connie heard her prognosis, she realized that her work with the microscope would be impossible. She eventually went back to school, obtained a master's degree in vocational rehabilitation, and began working for the state of California as a counsellor for the blind. As her own vision deteriorated further, she learned how helpless blind people could feel. "I had to ask to be guided to the ladies' room in a restaurant," she told me. "And if I dropped something, like my keys or cash, I had to search on my hands and knees for it."

Fifteen years ago, Connie lost her vision entirely. She is now seventy-six years old, a compact woman with a lively smile and hair the color of champagne. When I met her, she was dressed in slacks and a beige blouse, and her nails were painted fire-engine red. Last November, Connie volunteered to participate in a research study at the University of Southern California, in Los Angeles, where a device designed to restore some of the vision of R.P. sufferers is being tested. Connie agreed to have an artificial retina--a flexible, wafer-thin square grid of sixteen electrodes--implanted in her right eye. For the surgery, the eye muscles were paralyzed with injections of botulinum toxin. An ophthalmologist made an incision on the eye wall, threaded the electrode strip through the eye, and tacked it to her retina. Wires connected to the strip were buried under the skin near the eye. The wires ran to a magnetic disk sutured to her scalp just above her right ear.

"Here, you can feel it," Connie said, taking my hand and guiding it to the area above her ear. It felt like a small button.

Another piece of the device consisted of a pair of wraparound sunglasses with a miniature camera mounted on the bridge; the camera was attached to a wallet-size computer, which was connected to a coil taped above the ear, over the implanted magnetic disk. Connie put the glasses on, and the camera picked up the ambient light in the room and transmitted it to the coil in an intricate pattern of electrical impulses that were coordinated by the minicomputer. Once the impulses reached the coil, they were sent as radio waves to the magnetic disk and ultimately stimulated the electrode grid in Connie's retina. From there, the current passed through the optic nerve to the brain. In a normal eye, the cells of the optic nerve signal the brain according to a sequence known as the neural code. For Connie, that function was governed by proprietary software inside the minicomputer.

It was June, and we were in a laboratory at the university's Doheny Retina Institute, ...