SYDNEY, Aug. 29 (UPI) -- Australian researchers have announced they are developing a bionic eye that could return some sense of sight to blind people with hereditary degenerative diseases of the retina.
It is an advance that could do for the blind what the cochlear implant has done for the profoundly deaf, the researchers said.
The team, from the University of New South Wales and the University of Newcastle, has been working on the project since 1997. They said they are near to finding a way to replace the function of the damaged part of the eye.
Project leader Nigel Lovell told United Press International that trials of the device on sheep have evoked brainwaves consistent with vision.
"It shows we're heading in the right direction," he said.
The retina consists of a layer of light-sensitive nerve cells on the back of the eyeball. In a normal functional eye, a spot of light cast upon the retina triggers what the scientists call a "cascade of physiological events." This culminates in an electrochemical signal that spreads from retinal nerve cells, traveling along the optic nerve to the vision centers of the brain for interpretation.
In a diseased eye, the cascade no longer occurs, so there is no electrochemical signal to the brain.
Researchers have found the electrochemical signal can be initiated by delivering an electronic pulse to the appropriate nerve cells. That is what the bionic eye would do.
It would replace the eye lens with a capsule the size of a dime holding a microchip linked by platinum wires to the retina. The chip would receive pictures radioed from a tiny camera attached to a pair of glasses. Signals reaching the retina would produce 100 points of light, 10 rows wide and 10 columns deep, creating a pixilated image like those shown on television reports where a person's identity needs to be concealed.
"Down the road, it sounds pretty exciting," Robyn Richards, president of Retina Australia, told UPI. "I don't want people to get false hope, but the bionic eye could one day make a big difference to totally blind people."
Retina Australia is a voluntary organization that provides scientific research and support to people and families affected by retinal degenerative diseases.
An estimated 10 million Americans suffer from blinding eye diseases, such as macular degeneration and retinitis pigmentosa. The degeneration is gradual, typically starting with night blindness, then progressing to tunnel vision and then complete blindness.
People with the affliction also suffer sleeping disorders due to their inability to discern light from dark. To date, there is no cure or treatment.
In the United States, a parallel effort has been under way to develop an artificial vision system. Led by ophthalmologist Alan Chow of Chicago, it involves implanting a computer chip into the retina.
Lovell is keen to distance himself from the American device, however.
"The big difference is that in our bionic eye, the camera is outside the body," he said. "We don't believe Dr. Chow's invention will work because it is not bio-compatible. The body is a corrosive place and the electronics won't survive long. What's more, once the device inside the eye, if there are any problems, it will be impossible to extract it safely."
Lovell said the bionic eye will not restore perfect vision but could improve a patient's quality of life. As a start, he said, it would allow patients to discern night from day, probably relieving them of sleeping disorders.
In addition, patients might be able to detect movement and objects, which would help them get around without bumping into things. It might even be possible to read very large print in some cases.
It will be some time -- perhaps 5 years -- before the bionic eye will be commercially available, Lovell said. The next step is to test the device by implanting electrodes inside a person's eye for a day or so and recording what happens.
Lovell relates development of the device to cochlear implants. The first devices were not that successful, he said, and it was 20 years before Cochlear Ltd., a Sydney company, was able to put the device inside the human body.
The cochlear implants remain controversial. Last month, the U.S. Food and Drug Administration reported at least 25 cases of bacterial meningitis had been diagnosed worldwide among patients with the ear implants.
Richards, who has been legally blind since she was 38 -- after being diagnosed with retinitis pigmentosa at 33 -- said she hopes the research bears fruit.
"It will be great when it comes," she said, "but it would be dangerous for people like myself to get our hopes up too much at this stage."
