An update on retinal prostheses.

Retinal prostheses are designed to restore a basic sense of sight to people with profound vision loss. They require a relatively intact posterior visual pathway (optic nerve, lateral geniculate nucleus and visual cortex). Retinal implants are options for people with severe stages of retinal degenerative disease such as retinitis pigmentosa and age-related macular degeneration. There have now been three regulatory-approved retinal prostheses. Over five hundred patients have been implanted globally over the past 15 years. Devices generally provide an improved ability to localize high-contrast objects, navigate, and perform basic orientation tasks. Adverse events have included conjunctival erosion, retinal detachment, loss of light perception, and the need for revision surgery, but are rare. There are also specific device risks, including overstimulation (which could cause damage to the retina) or delamination of implanted components, but these are very unlikely. Current challenges include how to improve visual acuity, enlarge the field-of-view, and reduce a complex visual scene to its most salient components through image processing. This review encompasses the work of over 40 individual research groups who have built devices, developed stimulation strategies, or investigated the basic physiology underpinning retinal prostheses. Current technologies are summarized, along with future challenges that face the field.
Competing Interests: Funding and Declaration of Competing Interest LA receives licensing royalties for purchase by commercial entities for the IVI-VLV tool and is supported by a NHMRC Next Generation Fellowship (1151055) and an NHMRC Project Grant (1082358). GD is a consultant to Second Sight Medical Products (USA), and receives licensing royalties for purchase by commercial entities for the ULV-VFQ tool. JW is a consultant to Second Sight Medical Products (USA). BJ is supported by NIH grants R01 EY015128, R01 EY028927, a P30 EY014800 Vision Core Grant and an unrestricted grant from Research to Prevent Blindness to the Moran Eye Center. RH is an employee of Pixium Vision (France). MM is a consultant to Pixium Vision (France) and receives support from the National Institute for Health Research (NIHR) London Biomedical Research Centre (BRC) at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology. MP and NB receive funding from Bionic Vision Technologies (Australia). DR is supported by the German Ministry for Education and Research, BMBF 031a308.
(Copyright © 2019 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.)