Neurophysiological and medical considerations for better-performing microelectronic retinal prostheses.

Objective. Microelectronic retinal prostheses are a promising solution for sight restoration in cases of blindness caused by outer retinal degenerative diseases. Despite immense technological advances, the best visual acuity restored by microelectronic prostheses remains limited, implying poor understanding of the physiological underpinnings of retinal implants.Approach. In this perspective, we discuss the neurophysiological and medical issues that must be considered to substantially improve prosthetic performance.Main results. The eventual goal for retinal prostheses is to faithfully replicate neural signaling patterns arising in retinal ganglion cells (RGCs) during natural viewing. Two major challenges for microelectronic prostheses are 1) to reproduce intrinsically heterogeneous population codes of RGCs that originate from the remarkable diversity of retinal neurons and 2) to selectively activate specific RGC types to mimic the exclusive firing of ON and OFF channels. These fundamental challenges should be addressed to obtain high-quality artificial vision. To further develop prosthetic devices that are successful for long-term use, we discuss animal models for developing new surgical techniques and device testing. As an economic/ethical alternative to genetic modification, animal models of drug-induced outer retinal degeneration are discussed.Significance. Combined, the presenting perspective highlights the crucial issues for more successful retinal implants.