Choroidal vascularity index in eyes with central macular atrophy secondary to age-related macular degeneration and Stargardt disease

Purpose: To compare macular atrophy (MA) secondary to age-related macular degeneration (AMD) and Stargardt disease (STGD) using the choroidal vascularity index (CVI). Methods: In this multicentric retrospective study, two distinct cohorts were collected: patients with MA secondary to AMD and MA secondary to STGD. All patients were investigated using a multimodal imaging approach, including CVI in the subfoveal 1000 μm area. Of note, the CVI is not influenced by aging, which allows comparisons between different cohorts. Results: Seventy eyes were included: 35 eyes of 35 patients (mean age 78 ± 7 years) in the AMD group and 35 eyes of 35 patients (mean age 41 ± 16 years, p < 0.001) in the STGD group. Choroidal thickness was significantly lower in the AMD group in comparison to the STGD group (151 ± 80 μm vs 353 ± 105 μm, p < 0.001). The total choroidal area (TCA) was significantly greater in the STGD group in comparison to the AMD group (1.734 ± 0.958 mm2 vs 0.538 ± 0.391 mm2, respectively, p < 0.001). Interestingly, the CVI was significantly lower in AMD patients in comparison to STGD patients (27.322 ± 15.320% vs 49.880 ± 7.217%, respectively, p < 0.001), and this difference was confirmed in the subgroup of patients over 50 years old. Conclusion: Our results corroborate the hypothesis that large choroidal vessels were impaired to a greater extent in AMD than in STGD. CVI may help in differentiating AMD from STGD in the presence of MA, better understanding of the pathogenesis, and monitoring of therapeutic response.