Current retinal implants are too simplistic and do not account for distinct cell types transmitting visual information.

“the devices that have been implanted in humans so far by pioneering bioengineers who did really hard stuff were were fairly simple devices that treated the retina as if it's a camera that is just a grid of pixels and they put a grid of electrodes down there and they stimulated it according to the pixels in the visual world and thought well hopefully that will cause the retina to do the right thing and send a nice visual piece of visual information to the brain and initiate Vision Unfortunately they left the science on the table”