HORACE, N.D. - To get a glimmer of his sight back, Allan Peterson must learn to interpret the patterns of light a high-tech "bionic eye" system now feeds to his brain.
"That's what I'm in the process of beginning to do," the Horace man said Monday, March 19, venturing out of his tiny office on the second floor of the main North Dakota State University library.
"They (doctors) said it's like learning a new language," the 74-year-old said. "It's based on pulses of light. You have to figure out what the pulses mean."
Peterson started wearing the full Argus II Retinal Prosthesis System last week.
Several weeks ago, Peterson had a five-hour operation to implant a tiny chip "array" on the retina of his left eye. The chip is a vital part of the Argus II, created by the California-based firm Second Sight.
The other components include:
• Sunglasses with a tiny camera centered between the eyes and a "coil" or antenna on the left side that transmits signals to the retinal array via a Bluetooth connection.
• A small computer, about the size of an old school Walkman cassette player, which hangs on a lanyard around Peterson's neck. A data cord connects the computer to the glasses with its camera and antenna assemblies. The computer is fed video from the camera, which it processes to find differences in contrast, such as edges. It then turns that data into signals that are sent to the electrode array, which emits small pulses of electricity. The pulses bypass damaged photoreceptors and stimulate the retina's remaining cells. Those cells then transmit the visual information along the optic nerve to Peterson's brain, creating the perception of patterns of light.
Peterson said it took six hours to program the retinal array chip, which provides about 60 pixels of "vision."
When he turns on the system, "the pixels all wake up," which "is kind of cool," he said of the light pulses he sees.
Peterson grew up with normal vision. He was an assistant professor in the NDSU Department of Veterinary Medicine when he was diagnosed with retinitis pigmentosa in 1977. By 1988, the rare degenerative eye disease had left him legally blind. Over time, he lost all vision.
With the bionic eye system, Peterson has been able to discern the outline of a salad bowl and door frames by moving his head and interpreting the pulses of light transmitted to the array on his retina. He can also see pulses of light giving him an outline of people nearby, but it's not vision that includes color or gradations of black and white.
"The best you can hope for is an outline," Peterson said. "It isn't like the normal sight you had."
Peterson is one of about 230 people around the world who have been fitted with the bionic eye system, he said.
He has also agreed to be part of bionic eye studies at the University of Minnesota and University of Washington.
The device is approved by the Food and Drug Administration, so its cost was picked up by insurance, Peterson said.
The system is mentally taxing to use, he said.
"You can't use it for long periods of time, because you tend to get fatigued," Peterson said. "I'm going to start slow and I'll work up to it."