DOE supports artificial retina work

By SCOTT R. BURNELL, UPI Science News   |   Nov. 26, 2002 at 4:16 PM
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WASHINGTON, Nov. 26 (UPI) -- Some visually impaired people soon could benefit from a microchip electrode array designed to stimulate the optic nerve with simple image information, researchers said Tuesday.

The array, now the subject of $9 million in funding from the Department of Energy, would work on conditions such as macular degeneration, where the nerves still function but the eye is unable to transform light into signals the brain can interpret.

The Energy Department funding, spread over three years, will build on previous work supported by the National Science Foundation and the National Institute of Health's Eye Institute, said Mark Humayun a retinal surgeon and a biomedical engineer who has led the project at the University of Southern California's Doheny Eye Institute in Los Angeles.

"The Department of Energy labs have science and engineering that ... will greatly expedite the development of a retinal implant for the blind," Humayun said.

The Office of Naval Research and the Defense Advanced Research Projects Agency also have contributed to the effort, said Joel Davis, an ONR program manager in Arlington, Va. The office's work includes glass structures for mating the electrodes and the retina, he said.

"I'd be very surprised that if by the end of (the Energy Department funding), we don't have people walking around with embedded (retinal chips)," Davis told United Press International. "I can't tell you how well they're going to see, it's still in the R&D phase ... but these chips will be connected to some external camera."

Current prototypes of the device take the camera input and drive 16 electrodes, enough to differentiate between light and dark. The Energy Department research is aimed at devices with arrays of 100 electrodes on a side. The 1,000-electrode devices could produce crude images. Such an advanced array also could display written materials easily, Davis said, using a device similar to today's pen-style text readers.

Several Energy Department facilities -- including the Oak Ridge, Tenn., Lawrence Livermore, Calif., Los Alamos, Calif. national laboratories and the Sandia facilities in California and New Mexico -- will work with USC and North Carolina State University in Raleigh to improve and commercialize the device, Energy Secretary Spencer Abraham said Monday in announcing the funding.

Researchers still have to answer physiological questions, Davis said, including how long the optic nerve will remain usable once the eye stops transmitting information. They also need to determine the minimum amount of information needed for a usable sensory experience, he told UPI.

The Energy Department's effort will focus more on the engineering side of the device because the electrodes need to last for years without affecting the surrounding tissue adversely.

A specific challenge involves reducing the electrodes' size while maintaining their ability to transfer enough current to stimulate the eye's neurons. The smaller the electrodes get, the more vulnerable they are to corrosion, said Jack Judy, an assistant professor of electrical engineering at the University of California, Los Angeles, who has worked on the prototype array with Second Sight, a company in Valencia, Calif.

Some chemical processes involved in making computer chips hold a great deal of promise for manufacturing such small electrodes, Judy told UPI at a technical conference earlier this year. In order to get the most detail out of an array, engineers will also have to work out ways to shrink the contact points between the device's circuits and the electrodes.

The device holds a great deal of promise, said Betsy Zaborowski, director of special programs for the National Federation of the Blind in Baltimore, but people must remember the array cannot help every kind of blindness. Society must also remember sight restoration is not the only way for the blind to live productively, said Zaborowski, who is visually impaired.

"If modern science would devote significant resources and talent to the study and development of technology helpful to the blind in areas such as accessing information easily, traveling more efficiently and working to all of our capacities, we are confident (blindness) could be addressed more creatively," Zaborowski told UPI in an e-mail.

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