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New Study Shows Cones in Retinal Degeneration May Retain Visual Function

by B. E. Lewis, RDPFS Intern

New research from the University of California at Los Angeles (UCLA) suggests that cone photoreceptors in the degenerating retina of the eye considered “’dormant’” actually “continue to function, producing responses to light and driving retinal activity for vision.” The study’s authors state that their findings indicate that “therapeutic interventions to protect these cells…have the capability to preserve nearly normal daytime vision.” Their work focused on retinitis pigmentosa, a group of inherited diseases that cause photoreceptors to die, resulting in vision loss and eventual blindness. Rods and cones are the cells in the eye’s retina that are “responsible for the visual experience.”  Cones are active in daylight, rods in dim light. Mutations in rods causing them to die trigger most inherited retinal degeneration. Cones can remain alive after nearly all the rods die, but they retract key parts of the cells and appear “dormant.” Past literature suggested that dormant cells were not functional. “We showed that they were remarkably still active, although a lot less sensitive than normal,’” said senior author Alapakkam Sampath, the Grace and Walter Lantz Endowed Chair in Ophthalmology at the UCLA Jules Stein Eye Institute and professor at the David Geffen School of Medicine at UCLA. “’These important results may suggest a future path forward for patients with conditions thought to be causing irreversible retinal blindness…’” stated Dr. Steven Schwartz, Ahmanson chair in ophthalmology at the Geffen School and professor and Retina Division Chief at the Jules Stein Eye Institute. The next step in research is to determine to what extent the enhancement of the dormant cones will permit the revival of vision in various forms of blindness. To read the full report, visit the Science Direct/Current Biology webpage entitled “Cones and cone pathways remain functional in advanced retinal degeneration.” Additional details are available in the UCLA news release announcing that this “Early study shows cones in retinal degeneration, thought to be  dormant, may retain visual function” as well as coverage of the study in Medical News and Ophthalmology Times.