Current advances in the design of retinal and cortical visual prostheses

Low vision and ultimately, profound blindness can result from impaired connectivity or dysfunctional elements in the neural pathways transferring visual information to the brain. Blindness is one of the most debilitating sensory impairments affecting tens of millions of people worldwide, with its prevalence constantly increasing as the global population ages. Immense progress in the last decade has revealed the potential of electronic devices to restore visual perception through applying artificial electrical stimulation to neurons along the pathway from the eye to the brain. Prostheses implanted in the visual cortex, optic nerve, lateral geniculate nucleus, and the retina have led to elicitation of visual perceptions and improvement in functional visual ability in individuals with severe vision disorders. Here, we review the progress in visual bionics, focusing on retinal and cortical prostheses, and discuss key challenges and next-generation technologies.