Photos: Retinal implants

One of a number of efforts to restore vision lost to retinal disease, the Boston Retinal Implant Project is working on a wireless prosthesis that minimizes eye intrusion. Only a tiny plate of electrodes is implanted, communicating through radio waves with a larger chip attached to the outside of the eye. This chip gets image data and power from a coil on a pair of glasses.

The retinal implant developed under the lead of Doheny Eye Institute demands extensive surgery. The complicated insertion of several components takes six hours. So far, formerly blind people using the system have been able to detect simple shapes, objects and movements. Driving a car or reading a newspaper is still many years away.

In an eye suffering from age-related macular degeneration or retinitis pigmentosa, the photoreceptors of the retina die and eyesight is lost. A company called Optobionics is working on a chip that would be placed behind the retina, stimulating dying photoreceptors to continue translating light into neural signals.

The Optobionics Artificial Silicon Retina chip, here seen on a penny, is just a few millimeters in diameter and thinner than a human hair. The chip's surface is covered with microscopic solar cells that gather energy from light entering the eye.