A retinal implant of the eye developed would help the visually impaired people to stimulate the optic nerve with simple image information. The microchip electrode array designed 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, according to a United Press International report from Washington. Funding of $9 million from the Department of Energy is given for this research development.

Mark Humayun, a retinal surgeon and biomedical engineer who has led the project at the University of Southern California's Doheny Eye Institute in Los Angeles, said " the Department of Energy Labs have science and engineering that will greatly expedite the development of a retinal implant for the blind."

Joel Davis, an ONR Programme Manager in Arlington, Virgina, said, " I'd be very surprised that if by the end of (the Energy Dept funding), we don't have people walking around with embedded retinal chips. I can't tell you how well they are 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 Dept research is aimed at devices with arrays of 1000 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.

Researchers still have to answer physiological questions, David 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 said.

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 electrode's 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, Jack Judy, Asst 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, California, said.

Some chemical processes involved in making computer chips hold a great deal promise for manufacturing such small electrodes , Judy said at a technical conference earlier this year.

The device holds a great promise, said Betsy Zaborowski, Director of Special Programme 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 Betsy, 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, travelling more efficiently and working to all of our capacities, we are confident blindness could be addressed more creatively," Betsy said.