People with vision loss from retinal diseases might soon be fitted with a microchip that improves or restores their ability to see.

Dr. Eugene de Juan of Johns Hopkins University in Baltimore, Md., has placed electrode arrays on the retinas of 15 patients with eye disease. Under only localized anesthesia, the patients could identify electrode stimulation forms in the shape of the letter "H," a box, and vertical or horizontal lines. One patient saw a color.

Dr. de Juan says the next step in this research is the development of the electrode array into a chip that can be permanently implanted in the eye. He cautions, however, that a patient must have an intact optic nerve if he or she is to benefit from this technology.

Three companies are currently working to develop the microchip.