Thursday, June 26, 2008

"CHIPS: Next-generation artificial retina focuses on clinical trials"

A second-generation artificial retina chip called the Argus II Retinal Prosthesis System is beginning clinical trials. The new retina chip was designed at the University of California at Santa Cruz and fabricated by Second Sight Medical Products. The Argus II works by implanting the artificial retina chip directly inside the eye atop the old retina. An array of electrodes stimulates THE optic nerve cells, sending an image to the brain's vision centers. The plasticity of the brain's vision processing capabilities enable it to adapt to the artificially generated signals. A tiny wire connects the artificial retina to a circular antenna mounted around the pupil on the inside front of the eye. A video camera mounted on a pair of eyeglasses wirelessly transmits images to a belt pack containing a microprocessor that processes the video signal, then transmits it to the antenna in the eye, which in turn sends signals down the wire to directly stimulate optic nerves with the implanted electrode array. The electrode array was cast using a 1.2-micron CMOS process on a 5.5x5.25 millimeter die consuming 42 milliwatts. It achieves 4-bit resolution for each of the 60 implanted electrodes. Both power and data are supplied to the chip wirelessly.