In August 2018 researchers at Austin Texas university in collaboration with researchers at the Seoul university managed to develop a prototype of artificial retina based on a few layers of graphene that could be layered on a faulty retina to restore its functionality.
The layers act as light sensors and generate electrical spikes that are conveyed to the brain by the optical nerve whose terminations lay on the natural retina. The artificial one layered on the natural one would trick the nerve terminations into believing they are receiving the signals from the natural retina.
Mind you, this is not happening now, the prototype is just hinting on what might be possible. No trial has been performed so far on animals and human trials are still far away. There are still hurdles to solve (like how to place the artificial retina, power it up …) and of course several trials will be needed.
An artificial retina based on graphene (or other 2D structures like molybdenum disulphide) would be much better than a silicon based chip, like we have today (Argus II) because it can shape as a real retina providing a much larger field of vision with higher resolution.