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

Abstract

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.

Keywords: Macular ischemia; macular microcirculation; microvascular biomarkers; optical coherence tomography angiography; retinitis pigmentosa.

Figure 1

Representative multimodal retinal images from patients with typical retinitis pigmentosa (RP) with and without isolated macular lesions. Top row (T group): Fundus color photograph, fundus autofluorescence (FAF), and optical coherence tomography angiography (OCTA) images from a patient with typical RP without isolated macular lesions. FAF shows preserved macular autofluorescence with peripheral hypoautofluorescence. OCTA reveals generalized reduction of capillary density in both superficial and deep plexuses, without focal foveal involvement. Bottom row (T+M group): Images from a patient with typical RP with an isolated macular lesion. FAF demonstrates a well-demarcated hypoautofluorescent macular lesion surrounded by a hyperautofluorescent ring. OCTA reveals foveal avascular zone enlargement and marked reduction in vessel density in both superficial and deep capillary plexuses, indicating significant macular microvascular compromise. OCTA: Optical coherence tomography angiography, FAF: Fundus autofluorescence

Figure 2

Distribution of best-corrected visual acuity (BCVA) among normal controls and retinitis pigmentosa (RP) patients with or without isolated macular lesions. Box plots illustrate logMAR BCVA values in three groups: normal controls, typical RP patients without isolated macular lesions (T group), and those with isolated macular lesions (T+M group). Patients in the T+M group exhibited significantly worse and more variable visual acuity compared to the T group and controls (P = 0.002), reflecting greater central visual impairment. *indicate P<0.05, **indicate P<0.005 logMAR: Unit of visual acuity