The 21st century will be here before an artificial eye is, but research suggests that the artificial eye won't be far behind.
Two University of Utah bioengineers have set "achievable goals that we think could be improved upon." At this point, the research is basic and "we're a long way from a finished product," said Dr. Richard A. Normann, program director, who is collaborating with Dr. Kenneth Horch in the project.The concept is built on the fact that the visual cortex at the back of the brain remains functional even if the retina and optic nerve are irreversibly damaged. In normal sight, the visual cortex receives electrical signals through the optic nerve. A synapse or minute space between the two allows the cortex to remain functional even if it is receiving no such signals.
"It has been known for decades that if you pass an electrical current into the cortex, it mimics what the optic nerve does," said Normann. "It produces the perception of a flash of light."
The Utah scientists propose to build an array of electrodes to insert into the visual cortex. When these arrays are stimulated with electrical currents the recipient of such a device then should perceive an array of points of light, said Normann - "like a football scoreboard." Images most likely would be picked up by a very small TV camera mounted on spectacles. A connecter behind the ear would feed signals from the camera to the electrodes implanted in the cortex.
In preliminary research about 20 years ago, electrodes were placed on the surface of the cortex, Normann said. That preliminary research did prove that when electrical current was passed through the electrodes, the subjects could see spots of light.
"We intend that our electrodes will penetrate into the cortex, which will allow us to put electrodes closer together," he said. The current project envisions a 1-square-centimeter microchip of silicon containing approximately 1,000 electrodes.
Still, the surrogate visual sense will not be vision as a normal person has it. It is intended to give blind people mobility.
The University of Utah researchers are now using computer technology to design the microchip.
"Once we can produce them, we will implant them in animals to test their biocompatibility." That's 10 to 15 years away, Normann said.