[Epiretinal visual prostheses].

Epiretinal implants consist of a camera chip capturing the scene, a visual processor calculating retina-specific pulse sequences, a transponder for data and energy, and the implant itself. The implant consists of a receiver integrated into a posterior chamber lens, a microcable, and the retina stimulator. The stimulator is fixated onto the retinal surface using retinal tacks. In animal experiments it was shown that the materials being used were tolerated, the data and energy stream did not induce any adverse events, and that the fixation was feasible using retinal tacks. Stimulation of the inner retinal surface yielded a topographically correct activation of visual cortical areas. Even after a long history of blindness, tests in humans disclosed visual percepts.