First results of a study on a completely implanted retinal prosthesis in blind humans

A wireless epiretinal retina implant system, capable of stimulating the retinal ganglion cells in blind Retinitis Pigmentosa (RP) patients, was developed. The prosthesis itself is completely implanted into the eyeball, with no cable crossing the eyepsilas wall. Data and energy are provided by inductive coupling. The implant is based on a flexible polyimide tape with an integrated receiver coil, stimulation electrodes and microchips. The system was implanted into six legally blind patients for four weeks. All patients reported on visual sensations, evoked by electrical stimulation of their retina. The required stimulation thresholds were found to be very low. Implantation and explantation surgery were performed without complications. The implant was well tolerated for the duration of four weeks.