This technology is nothing new, but it has progressed quite a bit in the last few years. Eberthart Zrenner and colleagues at the University of Tübingen have developed a microchip carrying 1500 photosensitive diodes that slide into the retina where photoreceptors would usually be. Individuals with retinal dystrophy become blind due to the degeneration of photoreceptors and this new implanted microchip allows them to see. The diodes respond to light sending signals to the brain via an external power source connected to the eye by a wire.
The New Scientist Article with video below:
Electronic implant allows the blind to see