Interestingly there is another prosthetic device being developed according to an article in Scientific American. It doesn't involve eye surgery and big medical resources yet it accomplishes quite similar results. The sensor uses the tongue instead of the eye. Interesting but the tonge has its nerve endings very close to the surface and the number of endings is also quite large. Both methods allow the user to make out gross objects in a room and even seeing words on a page is a goal of the devices.