Earlier this year, three people were successfully implanted with a permanent “retinal prosthesis” by researchers at the Keck School of Medicine of the University of Southern California. Each patient wore spectacles with miniature video cameras that transmitted signals to a 4-mm-by-5-mm retinal implant via a wireless receiver embedded behind the ear.

The device works by transmitting visual signals captured by the video camera to the retinal implant, which contains an array of 16 electrodes. The signal is then recreated by stimulating the remaining healthy retinal cells with the electrodes, which pass on the information to the brain through the optic nerve.
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