Blind World


Artificial Vision.
Chips give some sight to patients.





June 29, 2004.

BY PATRICIA ANSTETT,
MEDICAL WRITER,
FREE PRESS.




The first 16 U.S. patients to receive artificial vision devices have crude improvements in sight, two leading teams told an international meeting last week.


One woman with severe vision impairment could see the color blue for the first time in 20 years, not the usual black and gray world of many visually impaired persons. She also could see the outline of her car in her driveway.


But for now, experts agreed, the devices are much like cochlear implants for the hearing-impaired: A promising technology that awaits refinement.


More significant gains are likely in the next generation of devices, experts said at a three-day conference, "The Eye and The Chip, World Congress on Artificial Vision," at Detroit's Westin-Detroit Metropolitan Airport Hotel.


"The technology is there but we are at least five years away from FDA approval" of a device, said Gerald Chader, chief scientific officer of the Foundation Fighting Blindness, an Owings, Md.-based nonprofit group promoting research in the field. He tells patients who aren't blind to wait.


There's a small risk patients would lose the residual vision they have, or rule themselves out for better implants down the road, he said.


The meeting, held every two years, provides updates about the emerging field of artificial vision, an evolving option for millions of people with blinding eye diseases.


About 3 million Americans have macular degeneration or retinitis pigmentosa, diseases that lead to severe vision impairment and blindness.


Teams from Chicago and Los Angeles reported follow-up studies, up to four years after implant surgery, for the first 16 patients. The latest patients had the surgery Wednesday.


The teams are among a half dozen worldwide working to produce the world's first approved artificial vision device.


Wayne State University School of Medicine is studying how growth factors manufactured by the human body might be used to enhance vision signals created by the devices.


Dr. Raymond Iezzi, an ophthalmologist at the Kresge Eye Institute, affiliated with WSU and the Detroit Medical Center, said that these growth factors may extend the life of computer chips in the implants and have a therapeutic benefit for numerous other eye-related diseases, the same way medicine-coated stents are producing better outcomes for people undergoing artery-widening angioplasty.


"The chip is not going to last forever," he explained. Diseased eyes "will continue to deteriorate," he said. "This may help slow the degenerative process and give extra life to the implant, hopefully for many years."


The WSU team is working on repeating the studies before beginning studies in humans, Iezzi said. Another team headed by Nicolas Cottaris and Sylvia Elfar is carrying out meticulous research to plot which neurons in the eye respond to electrical stimulation and which don't. Knowing which do may help surgeons better place the implants, and help determine what type of vision might be expected from them, the team said.


Artificial vision implants use models with 16 tiny electrodes stretched along a strip the size of a matchstick.


The electrodes send signals to the remaining neurons in the retina. They transmit them as radio waves to a camera inside glasses or goggles a person wears before they are relayed to the optic nerve.


Kelly McClure, director of research and development for Second Sight, a Sylmar, Calif., firm involved in one of two ongoing clinical studies of the retinal devices, said he expects significant improvements from models his firm hopes to test soon.


"Anybody can make a signal-processing system and a lot of them do," McClure said. "The trick is to get more and more hardware on it. It's all about the electrodes. That's the hard part."


For now, "patients are well informed that they won't achieve functionality with this implant," McClure said. "They're doing it more for science."


Dr. Mark Humayun, with the University of California, reported on the first six patients to receive retinal implants from Second Sight. Optobionics, a Wheaton, Ill., firm begun by ophthalmologist Dr. Alan Chow and his engineer brother, Vincent, reported on results of the 10 patients who used their device.


Some of the gains decline two years after the devices are implanted, but most patients "still have better vision" than they had before the surgery, Chow said.


All of the patients appeared to handle the surgery well and developed no complications as a result of it, Chow said.



For details, visit Second Sight, www.2-sight.com; Optobionics at www.optobionics.com; or the Foundation for Fighting Blindness, www.blindness.org.



Copyright 2004 Detroit Free Press Inc.



http://www.freep.com/news/health/chip29_20040629.htm.




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