Newswise — Rockville, Md. – New research suggests patients with congenital cone dysfunction may also experience abnormalities with their rod distribution, potentially impacting efficacy of therapeutic approaches for inherited cone disorders. The study presented this week at the 2021 Annual Meeting of the Association for Research in Vision and Ophthalmology (ARVO) — being hosted virtually — used high-resolution imaging to assess cone and rod structure in patients who lack normal function in two of the three cone types.

With the emergence of novel therapeutic approaches leading to clinical trials involving inherited cone disorders, Emily J. Patterson, PhD, of the University College London Institute of Ophthalmology, sought to understand the potential effects on not just the cone cells, but also on neighboring rod cells. “Although we know that X-linked cone dysfunction can cause disruption to both the structure and function of the cones, it has not been confirmed as to whether there is a knock-on effect on rods. Elucidation of the different factors that affect the rod mosaic may apply not only to X-linked cone dysfunction but also to other cone-related disorders,” she says.

Patterson and her team’s data suggest that in patients who lack expression of the normal L and M opsin genes, rod density and/or distribution within the retina may be affected differently. For instance, select genotypes appear to be associated with lower rod density than normal. Further, one genotype appears to have a “flatter” distribution of rods across the range of eccentricities assessed, indicating abnormalities in developmental rod/cone migration, or redistribution of rods following cone degeneration. Knowledge about the relationship between genotype and rod/cone structure may help to inform participant stratification and manage expectations for future therapy efforts.

On presenting her research at the ARVO Annual Meeting, Patterson says she is excited to engage her research with experts and colleagues from the around the world, noting, “the virtual format makes the meeting even more accessible for members across the globe.”

Abstract title: Macular rod and cone photoreceptor structure in patients with X-linked cone dysfunction

Presentation start/end time: Saturday, May 1, 2021,10:15am – 12noon ET

Presentation number: 3528561



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The Association for Research in Vision and Ophthalmology (ARVO) is the largest eye and vision research organization in the world. Members include approximately 10,000 eye and vision researchers from over 75 countries. ARVO advances research worldwide into understanding the visual system and preventing, treating and curing its disorders. Learn more at

Meeting Link: 2021 Annual Meeting of the Association for Research in Vision and Ophthalmology (ARVO)