Electronic approaches to restoration of sight

Abstract

Retinal prostheses are a promising means for restoring sight to patients blinded by the gradual atrophy of photoreceptors due to retinal degeneration. They are designed to reintroduce information into the visual system by electrically stimulating surviving neurons in the retina. This review outlines the concepts and technologies behind two major approaches to retinal prosthetics: epiretinal and subretinal. We describe how the visual system responds to electrical stimulation. We highlight major differences between direct encoding of the retinal output with epiretinal stimulation, and network-mediated response with subretinal stimulation. We summarize results of pre-clinical evaluation of prosthetic visual functions in- and ex-vivo, as well as the outcomes of current clinical trials of various retinal implants. We also briefly review alternative, non-electronic, approaches to restoration of sight to the blind, and conclude by suggesting some perspectives for future advancement in the field.

Reconstruction of natural images from responses of primate retinal ganglion cells

“…Using reconstruction to understand the signals transmitted by neurons may be increasingly important in future efforts to read and write neural codes using brain-machine interfaces (BMIs). In the retina, certain types of blindness can be treated with implants that use electrical stimulation to activate the remaining retinal neurons (Goetz & Palanker, 2016), and the visual messages described in the present work can help guide the selection of optimal stimulation patterns (Goetz & Palanker, 2016;Golden et al, 2019;Shah et al, 2019). Reconstruction can also be used to compare the evoked visual representation with the representation produced by natural neural activity.…”

Local photoreceptor degeneration causes local pathophysiological remodeling of retinal neurons

“…This includes those generated by optoelectronic or optogenetic tools, by photoreceptors regenerated from stem cells, or by photoswitches such as BENAQ. RAR inhibitors might be particularly effective in improving prosthetic vision enabled by a subretinal optoelectronic implant, which stimulates inner retinal neurons in the scotoma of patients with advanced AMD (28).…”

Toward the Next Generation of Retinal Neuroprosthesis: Visual Computation with Spikes

“…Here we only focused on the computational modelling issue of one type of retinal neuroprosthsis with electrodes embedded. Certainly, for retinal neuroprosthsis, as an engineering system, there are many parallel difficult issues, such as advanced materials, power designing, communication efficiency, and other related hardware issues, which have been covered by many wellwritten reviews [16,18,13,15]. One should note that there are different types of visual implants, including those with light retinal stimulation such as optogenetics and chemical photoswitches, as well as implants in other parts, beyond the retina, of the brain.…”