The intraocular retinal prosthesis, or "eye chip," uses a small video camera in a set of goggles to send images to the microchip fastened to the back of the retina. Electrodes on the chip form an image that can stimulate the retina and be "seen" by blind people.
"The beauty of it is that you're hooked up to the most powerful computer in the world, which is the human brain," said Dr. Mark Humayun, an ophthalmologist at Johns Hopkins Hospital's Wilmer Eye Institute.
Last week, Stevie Wonder said he was considering surgery to implant the chip. Wonder, who has been blind since birth, spoke with Humayun, who offered to examine the 49-year-old singer. Humayun said the surgery is unlikely to help Wonder, but wouldn't rule it out.
If planned animal and human trials are successful, the eye chip could be available in two to five years.
Humayun said the prosthetic eyes would probably be most useful for people who saw at one time or whose eyesight is worsening due to a condition such as macular degeneration, the major cause of blindness in the elderly.
Wilmer scientists are developing the prosthetic eyes along with electrical engineers at North Carolina State University.
The system hasn't been tested on humans, but researchers have been conducting tests on its components for a decade. Seventeen patients have had tiny electrodes inserted directly into the retina for a few minutes in the operating room. Most have been able to recognize light and a few have identified lighted forms and colors, Humayun said.