Geographic disparities in the distribution of ISGEDR-affiliated ocular genetics physicians relative to retinitis pigmentosa burden

Introduction Professional societies often serve as a hub for research advances and treatment expertise. As the field of ocular genetics rapidly expands, with the advent of gene-based diagnostics and emerging therapies for inherited retinal diseases, we sought to understand whether the worldwide geographic distribution of professionally affiliated ocular genetics physicians allows for equitable access to this service.Methods We evaluated the geographic distribution of physicians affiliated with the International Society for Genetic Eye Disease and Retinoblastoma (ISGEDR), a major professional society for ocular genetics specialists, against the estimated prevalence of retinitis pigmentosa (RP), the most common inherited retinal disease.Results Across 37 countries, we identified 185 ISGEDR-affiliated physicians, with 47% located in North America and 31% in Europe, while large regions of Africa, Asia, South America, and the Middle East had no ISGEDR physicians. Among represented countries, estimated RP patient-to-physician ratios varied more than 400-fold and increased significantly with larger land area and lower national income. In the United States, 46% of states lacked an ISGEDR physician, and RP burden among represented states varied more than 40-fold, increasing significantly with larger land area. Voronoi mapping of the contiguous United States demonstrated substantial variation in catchment size, with the largest expected travel-burden regions in the Mountain West.Discussion These findings reveal substantial geographic inequities in the distribution of ISGEDR-affiliated ocular genetics physicians relative to RP burden. This under-representation may reflect a shortage of ocular genetics physicians and/or barriers to professional affiliation within identified regions, suggesting a need for more scalable models of ocular genetics care.