Gene therapy in color vision deficiency: a review.

BACKGROUND: Color vision deficiencies are a group of vision disorders, characterized by abnormal color discrimination. They include red-green color blindness, yellow-blue color blindness and achromatopsia, among others. The deficiencies are caused by mutations in the genes coding for various components of retinal cones. Gene therapy is rising as a promising therapeutic modality. The purpose of this review article is to explore the available literature on gene therapy in the different forms of color vision deficiencies. METHODS: A thorough literature review was performed on PubMed using the keywords: color vision deficiencies, gene therapy, achromatopsia and the various genes responsible for this condition (OPN1LW, OPN1MW, ATF6, CNGA3, CNGB3, GNAT2, PDE6H, and PDE6C). RESULTS: Various adenovirus vectors have been deployed to test the efficacy of gene therapy for achromatopsia in animals and humans. Gene therapy trials in humans and animals targeting mutations in CNGA3 have been performed, demonstrating an improvement in electroretinogram (ERG)-investigated cone cell functionality. Similar outcomes have been reported for experimental studies on other genes (CNGB3, GNAT2, M- and L-opsin). It has also been reported that delivering the genes via intravitreal rather than subretinal injections could be safer. There are currently 3 ongoing human clinical trials for the treatment of achromatopsia due to mutations in CNGB3 and CNGA3. CONCLUSION: Experimental studies and clinical trials generally showed improvement in ERG-investigated cone cell functionality and visually elicited behavior. Gene therapy is a promising novel therapeutic modality in color vision deficiencies.

A Review of Driving and Binocularity.

Although most jurisdictions allow stereoscopically deficient and monocular individuals to drive, studies regarding these visual components' effects on driving have to date yielded contradicting results. Interviews, record reviews, and experiments have been used to unmask these effects. In interviews, participants with amblyopia reported several difficulties operating automobiles. Record reviews yielded mixed results, with studies revealing an increased crash rate and/or severity in a group of stereoscopically deficient commercial drivers, whereas studies of non-commercial drivers failed to make that association. Furthermore, experimental studies showed that individuals with reduced stereopsis braked earlier and were less likely to crash. With regard to monocularity, real-life experiments failed to demonstrate a poorer driving performance and simulation studies showed that drivers with sudden monocularity were more likely to crash and drive off the road. [J Pediatr Ophthalmol Strabismus. 2022;59(1):6-12.].