New research from a team including scientists from the John A. Moran Eye Center at the University of Utah provides insight on how people with retinal degenerative disease can maintain their night vision for a relatively long period of time.
A study published in the journal eLife suggests that second-order neurons in the retina, which relay visual signals to the retinal ganglion cells that project into the brain, play a key role. These neurons are able to maintain their activity in response to the degeneration of rod photoreceptors, or the cells responsible for allowing us to see at night. It’s a process known as homeostatic plasticity.
Studying a model of retinitis pigmentosa, researchers determined the degeneration of rod photoreceptors triggered genomic and molecular changes in the retina and increased electrical signaling between rod photoreceptors and rod bipolar cells. These changes were associated with well-maintained behavioral night vision despite extensive photoreceptor cell loss.
“This mechanism may explain why patients with inherited retinal diseases can maintain their normal vision until the disease reaches a relatively advanced state,” said study co-first author Nguyen Pham, a graduate research assistant at the Moran Eye Center lab of Frans Vinberg, PhD. “It could also inspire novel treatment strategies for diseases that lead to blindness.”
“Our results suggest retinal adaptation as the driver of persistent visual function during photoreceptor degenerative disease,” said Dr. Vinberg. “Additional research is now needed to discover the exact homeostatic plasticity mechanisms that promote cellular signaling and visual function. This could help inform the development of potential new interventions to enhance homeostatic plasticity when needed.”
Study authors included Pham, Vinberg, Henri Leinonen, Taylor Boyd, Johanes Santoso, and Krzysztof Palczewski.
Funding for the research was provided by: National Eye Institute (R00 EY026651) (R01 EY009339) (R24 EY027283); Research to Prevent Blindness (Unrestricted grant to the Department of Ophthalmology and Visual Sciences, University of Utah); International Retinal Research Foundation (Regular Grant); Research to Prevent Blindness (Dr. H. James and Carole Free Career Development); Eye and Tissue Bank Foundation (Postdoctoral Award), Finnish Cultural Foundation (Postdoctoral Award); Orion Research Foundation (Postdoctoral Award); Research to Prevent Blindness (Unrestricted grant to the Department of Ophthalmology, University of California, Irvine).