Implanted Wires Let Blind Woman ‘See’ Dots of Light

Tiny electrodes implanted in a blind woman’s brain allowed her to “see” distinct dots of light--a method that may produce an artificial vision device in several years, doctors said Thursday.

The experiment “gives us firm evidence that artificial vision for the blinded person is an achievable goal, hopefully before the end of the decade,” said Dr. Murray Goldstein, director of the National Institute of Neurological Disorders and Stroke.

“Our initial goal is to develop a stadium scoreboard type of display so they could read printed material and recognize street signs,” navigate through doorways and avoid obstacles, said Dr. Terry Hambrecht, an institute physician.

The government experiment, part of a 20-year, $10-million research effort, was revealed during the annual meeting of the Society for Neuroscience. It was kept secret because “we didn’t want to spread false hope if the experiment failed,” Goldstein said.

The experiment on the 42-year-old blind woman started when she underwent surgery in November, 1991, at the National Institutes of Health Clinical Center in Bethesda, Md. The woman, a volunteer whose identity was not disclosed, lost her eyesight due to glaucoma 20 years ago, Hambrecht said.

During her operation, Drs. Conrad Kufta and Daniel O’Rourke removed a 1-by-2-inch section of her skull and implanted 38 “microelectrodes” into her visual cortex, the part of the brain that receives signals from the eyes.

Tiny gold wires attached to each electrode protruded from her skull. When electric currents were applied to the wires, 34 of the 38 electrodes worked, allowing her to “see” 34 dots of blue, purple, red and yellow light that ranged from the size of a pinhead to the size of a nickel held at arm’s length and that could be adjusted in brightness.

Hambrecht and other researchers mapped where each electrode produced a dot in the woman’s perceived field of vision. That let them apply current to four electrodes so the woman could “see” the letter I , he said.

Eventually, scientists envision a device that would include a miniature television camera attached to eyeglasses frames: The TV picture of a blind person’s surroundings would be sent to electrodes permanently implanted in the brain and the user would experience the sensation of seeing a picture made up of 250 to 1,000 spots of light.