Choroidal structural analysis and vascularity index in retinal dystrophies

Abstract

Purpose: To assess choroidal structural changes in patients with retinal dystrophies using choroidal vascularity index (CVI), a novel optical coherence tomography (OCT) based tool. Methods: This retrospective study included 26 patients with retinal dystrophies (17 with retinitis pigmentosa, four with Stargardt disease, three with cone-rod dystrophy, one each with Best disease and Bietti crystalline dystrophy) and 32 healthy controls. Subfoveal OCT images were used for analysis. Mean CVI was compared between retinal dystrophy and control group, as well as among the retinal dystrophy subgroups. Results: Mean CVI in eyes with retinal dystrophies was 52 ± 9% and it was significantly lower compared to that in normal eyes (70 ± 3%, p < 0.001). The differences among subgroups of retinal dystrophy were not statistically significant (p = 0.084). All types of retinal dystrophy were associated with lower CVI (all p < 0.001), after adjusting for age, gender, visual acuity and duration of symptoms. Older age was also shown to be independently associated with lower CVI (p = 0.012). Gender, visual acuity (VA) and duration of symptoms did not significantly affect CVI. Conclusion: Decreased choroidal vascularity was seen in eyes with retinal dystrophies. (CVI) may be a helpful tool in monitoring choroidal involvement in retinal dystrophies.