Biological Sciences 300/301, Smith College | Neurophysiology

Case 5: Which approach to restoring vision seems the most promising?

This case discussion is based on an article that summarizes recent efforts to develop approaches for restoring sight in blind and visually impaired people. The introductory section is reproduced below; the full article can be found online.



Sight restoration: Prosthetics, optogenetics and gene therapy

Ione Fine, Connie L. Cepko and Michael S. Landy
Vision Research, Volume 111, Part B, June 2015, Pages 115-123

This special issue is inspired by the wide variety of innovative approaches that are currently being developed to prolong or partially restore vision. Our primary goal was to provide an integrated discussion of these various approaches in a single volume. Current sight restoration research involves a wide range of technologies that vary greatly both in their underlying scientific methodologies and in the challenges that they face. As a result, different approaches have rarely been discussed within an integrated literature, making it difficult to compare their relative opportunities and challenges in this rapidly developing field. This is a particularly timely moment for such a special issue. An extraordinary variety of potential therapies have begun, or are about to begin clinical trials, and one variant of retinal prosthesis is on the market in both Europe and America.

This editorial review is heavily inspired by the many contributors to the US National Eye Institute's Audacious Goals meeting of 2013, in which leaders in the field were given the opportunity to discuss the opportunities and challenges offered by current sight restoration technologies. Probably all of the interesting ideas of this editorial should be attributed to one of the many attendees who contributed to the discussion. Any incorrect or foolish ideas are of course entirely our own.

A wide variety of approaches towards sight restoration are currently being actively researched (e.g. Mellough et al., 2014, Nagel-Wolfrum et al., 2014 and Pearson et al., 2014). This special issue focusses on three main approaches that primarily focus on alleviating the effects of photoreceptor diseases and are currently in, or are approaching, clinical trial status. Gene therapies use the delivery of genes to directly compensate for the loss of function of a disease gene, or, alternatively, use genes such as growth factors to generically prolong the life and functioning of photoreceptors. Optogenetics and small molecule photoswitches endow retinal cells with the ability to sense light by creating novel (or modulating existing) light-sensitive ion channels or pumps. Finally retinal and cortical prostheses use electrical stimulation to directly elicit neural responses.

Cross-section through the retina
showing the fovea.

GC =ganglion cells
INL =inner nuclear layer
ONL =outer nuclear layer
C =cones