Experiments have revealed that by stimulating the retina with preprogrammed configurations of ultrasound, some blind people are able to see black and white outlines and images.
A healthy retina has a natural ability to retain images that is called persistence of vision. It is persistence of vision that allows us to see continuous, smooth movement in film. A movie projector throws about 24 still images on a screen in one second. But each picture on the screen is presented to the eye before the previous image in the brain fades on our retina, so that one image seems to merge into the next.
So if cameras can successfully digitize images and translate them into recognizable ultrasound impulses for the retina and the brain, we may well be witness to the birth of yet another astounding human sense — virtual sight!