The Argus II system can restore some vision in people made blind by retinitis pigmentosa. The patient wears a pair of glasses with a small video camera mounted on it, which captures images. courtesy Second Sight Medical Products, Inc
A prosthesis no larger than a pencil eraser is surgically implanted on the surface of the retina. courtesy Second Sight Medical Products, Inc
Visual information from the camera is transmitted wirelessly to electrodes on the artificial retina, where it is converted to electrical pulses.
Any remaining cells that haven't been damaged by the disease are stimulated by the pulses, leading to a perception of light patterns in the brain. courtesy Second Sight Medical Products, Inc
Roger Pontz was left completely blind by retinitis pigmentosa. In January 2014 he became the second person in the United States to get the implant. CNN
Retinitis pigmentosa causes a slow loss of light-sensitive retinal cells. CNN
The surgery itself lasts around four hours, but it can be a number of weeks before the device is switched on and the patient is able to see using it. CNN