by Tom Hoglund
Information Officer, Foundation Fighting Blindness
For the first time ever, researchers from a company called Optobionics surgically implanted an artificial retina into three patients who are blind from retinitis pigmentosa. These highly-experimental prosthetic devices, made of silicon computer chips, are intended to restore ambulatory vision, thereby giving people the freedom to walk without the assistance of a cane or guide dog.
The company’s device, called an Artificial Silicon Retina (ASR), is designed to function much like a photoreceptor cell in the retina. In retinal degenerative diseases, such as RP, macular degeneration and Usher syndrome, photoreceptor cells degenerate and die. In studies, supported by The Foundation Fighting Blindness, researchers found that, despite the loss of photoreceptors, much of the remaining nerve cell network in the retina remains relatively healthy. This finding led researchers to begin developing computer chips that might function in place of photoreceptor cells.
The ASR is 2 millimeters in diameter and one-thousandth of an inch in thickness, making it thinner than a human hair. It contains 3500 solar cells that are designed to convert light into electrical signals. Optobionics is based out of Chicago and headed by Dr. Alan Chow. Dr. Chow is a member of The Foundation Fighting Blindness’ Surgical and Implant Advisory Committee.
According to Dr. Chow, these experimental implants are part of a Food and Drug Administration approved feasibility and safety study to see whether the device can be safely implanted and whether it is well-tolerated in the human eye. For these three operations, Dr. Chow implanted a smaller version of the ASR device in the periphery, or side, of the retina. Dr. Chow also hopes to gauge whether patients gain any visual perception where the chip is implanted. The operations, performed on June 28 and 29, reportedly went well and the patients are at home recovering from the surgery.
In the past, researchers have performed very brief experiments to stimulate the retina in patients without vision. However, this is the first time anyone has implanted a device in humans. Although there is still a great deal of remaining research before such a device will be available to patients, news of these first-ever surgeries is a sign that artificial retinas are advancing toward clinical trials.
Several other research groups are working to develop an artificial retina. The Foundation currently supports two groups: Dr. Eugene de Juan and Mark Humayun of The Foundation’s Research Center at Johns Hopkins University, and Drs. Joseph Rizzo and John Wyatt, of Harvard Medical School and Massachusetts Institute of Technology, respectively. The Foundation also supports Dr. Richard Normann at the University of Utah, who is developing a silicon chip to be implanted in the visual cortex of the brain.