Myopic patchy atrophy differs from geographic atrophy in retinal pigment epithelium appearance and intraretinal hyperreflective foci

To assess clinical-histological characteristics of myopic patchy atrophy (PA) and geographic atrophy of age-related macular degeneration (GA). Participants of population-based studies (Ural Eye and Medical Study (n = 5899; age: 40 + years), Ural Very Old Study (n = 1526; age: 85 + years), Beijing Eye Study (n = 3468; age: 40 + years) were clinically examined. We additionally assessed histologically human globes (n = 446) enucleated due to clinical reasons or enucleated post mortem. In the population-based studies, GA and PA were detected in 79 eyes (age: 81.9 ± 12.0 years;axial length: 23.0 ± 0.9 mm) and 59 eyes (age:70.1 ± 12.3 years;axial length: 28.2 ± 2.2 mm), respectively. The GA group versus PA group had a higher degree of intraretinal hyperreflective foci (iHRFs) (3.6 ± 1.1 versus 0.2 ± 0.7; p < 0.001) and para-lesional retinal pigment epithelium (RPE) irregularities (3.9 ± 1.0 versus 0.1 ± 0.6; p < 0.001), higher prevalence of outer nuclear layer thinning (72/79 (91.1%; 95% CI 79,100) versus 36/59 (61.0%; 95% CI 41,82); p < 0.001),and lower prevalence of Bruch´s membrane (BM) defects (0% versus 35/59 (59.3%; 95% CI 40,78)). PAs showed BM defects with absence of choriocapillaris, while in GAs, BM and choriocapillaris were intact. In all eyes with GAs and PAs, the ellipsoid zone and external limiting membrane were defect or absent. Similar findings were obtained upon histology, with intraretinally located RPE cells in GAs in contrast to PAs as additional finding. PA and GA have in common the presence of an RPE-layer opening, and they differ in continuity of BM and adjacent choroidal structures, RPE appearance and prevalence of iHRFs. PAs may be due to an axial elongation-related expansion opening in the RPE layer without marked RPE reaction, while GAs may be associated with a primary RPE reaction including intraretinal RPE cell migration.