Aug. 9, 2001 A new electronic retina implanted in three patients last week is one of several projects under way by research groups around the world designed to fill in for damaged cells and possibly restore lost vision, The New York Times reported.

Last week’s surgeries, at two Illinois hospitals, are part of a federally approved study that allows the devices to be placed in 10 volunteers. Optobionics of Wheaton, Ill., produced the silicon implant, which uses about 3,500 miniature light detectors attached to metal electrodes to imitate function of an eye’s photoreceptors, or rods and cones, the report said.

The chip is designed to treat retinitis pigmentosa and macular degeneration, diseases that affect the photoreceptors.

Different approaches to treating eye diseases are being developed at several institutions, including the Harvard-MIT Retinal Implant Project, the University Eye Hospital in Germany and the Wilmer Ophthalmological Institute at Johns Hopkins Hospital in Baltimore.