Optical Coherence Tomography-Based Choroidal Structural Analysis and Vascularity Index in Best Vitelliform Macular Dystrophy

INTRODUCTION: This study investigated choroidal structural changes on optical coherence tomography (OCT) using choroidal vascularity index (CVI) and choroidal thickness (CT) in patients with Best vitelliform macular dystrophy (BVMD). METHODS: This retrospective case control study included 78 patients with BVMD of different clinical stages and 242 age- and gender-matched healthy controls. Subfoveal OCT scans were analysed. Total choroidal area (TCA), luminal area (LA) and CT were measured after image segmentation and binarization. CVI, a novel marker for choroidal angioarchitecture, was defined as the ratio of LA to TCA. CVI and CT were compared between BVMD and control group, as well as among the BVMD subgroups. RESULTS: Mean CVI was lower in eyes with BVMD (65.0 ± 3.5%) compared to that in control eyes (67.5 ± 3.9%) and this was statistically significant (p < 0.0001). There was no significant difference in subfoveal CT between BVMD (302.88 ± 81.68 μm) and control (309.31 ± 65.46 μm) eyes (p = 0.4799). In the subgroup analysis, all stages of BVMD showed lower CVI compared to control while SFCT remained similar. Within the BVMD subgroups, CVI and subfoveal CT did not differ significantly and both were not shown to be associated with visual acuity. CONCLUSION: Decreased CVI was shown in eyes with BVMD compared to control eyes, while no significant difference in subfoveal CT was seen. CVI may be helpful in the understanding of choroidal pathology in BVMD.