Optical coherence tomography angiography characteristics of microvascular retinal alterations and the relationship with visual impairment in different patterns of retinitis pigmentosa

PURPOSE: The purpose of the study was to evaluate macular microvascular alterations using optical coherence tomography angiography (OCTA) in typical retinitis pigmentosa (RP) patients with and without isolated macular lesions, and to assess their relationship with best-corrected visual acuity (BCVA). MATERIALS AND METHODS: This retrospective study included 77 patients with typical RP from the Taiwan Inherited Retinal Degeneration Project, categorized into two groups: with isolated macular lesions (T+M, n = 44) and without (T, n = 33). Eighteen age-matched healthy individuals served as controls. All participants underwent comprehensive ophthalmic examinations and OCTA imaging. Quantitative parameters–vessel density in superficial and deep retinal plexuses, foveal avascular zone (FAZ) area, and outer retinal flow–were analyzed and correlated with BCVA. RESULTS: Both RP groups showed compromised macular microcirculation compared to controls. FAZ area was significantly larger in the T+M group than in controls ( P = 0.01) and showed a trend toward enlargement compared to the T group ( P = 0.06). BCVA was significantly worse in the T+M group than in the T group and controls ( P = 0.002). In the T+M group, decreased vessel density in the deep plexus, enlarged FAZ, and reduced outer retinal flow were significantly correlated with poorer vision; these correlations were not observed in the T group. CONCLUSION: Macular microvascular impairment is a common feature in typical RP, but its association with central visual loss is particularly pronounced in those with isolated macular lesions. OCTA parameters may serve as useful biomarkers for clinical monitoring and prognosis in this subgroup.