Retinal and choroidal morphometric analysis in fellow eye of unilateral wet age related macular degeneration using optical coherence tomography angiography

Abstract Background : Age-related macular degeneration (AMD) when associated with macular neovascularization can cause severe visual morbidity. This study aims to evaluate the retinal and choroidal microvascular alterations using optical coherence tomography angiography (OCTA) in eyes with unilateral wet age-related macular degeneration (AMD) termed as “affected eye” (AE) and compare it with their fellow eyes (FE). Methods : This cross-sectional study included 60 patients (120 eyes) with age over 50 years. Vessel density (VD), perfusion density (PD), and foveal avascular zone (FAZ) in the superficial capillary plexuses (SCP), deep capillary plexus (DCP) and avascular layer were assessed using OCTA. Enhanced depth imaging was used to evaluate subfoveal choroidal thickness (SFCT) and choroidal vascularity index (CVI). Results : The mean age was 73.9±9.54 years (51-89 years) with 51.7% male. Quantitative OCTA analysis showed no significant inter-eye differences in VD or PD in SCP or DCP (p > 0.05). However, FAZ was significantly enlarged in affected eyes compared with fellow eyes in SCP (0.91 ± 0.40 vs 0.64 ± 0.20 mm²; p < 0.001) and DCP (p < 0.001). FAZ enlargement in the avascular layer was not statistically significant (p 0.20). Pattern I macular neovascular membrane (MNV) was significantly associated with the shape, presence of anastomoses, and overall activity scores. Inter-eye differences choroidal parameters were statistically significant for SFCT (p 0.019), haller layer (p 0.014) and CVI (p < 0.001). AE status was significantly associated with age, smoking, and lens status. Conclusion : FAZ enlargement represents the most sensitive OCTA parameter distinguishing AE from FE in unilateral wet AMD. OCTA-based assessment of FE may aid in detecting early microvascular alterations and guiding timely intervention as they exhibit early AMD changes, which may be potentiated by retinal and choroidal vascular insufficiency.