Choroidal vascularity index determined by binarization of enhanced depth imaging optical coherence tomography images in eyes with intermediate age-related macular degeneration

Purpose To evaluate choroidal structural changes in patients with intermediate age-related macular degeneration using choroidal vascularity index. Methods The eyes of patients with intermediate age-related macular degeneration and controls were evaluated with enhanced depth imaging optical coherence tomography images. Subfoveal choroidal area was segmented into luminal area and stromal area by the binarization technique on enhanced depth imaging optical coherence tomography images using ImageJ software. Choroidal vascularity index was defined as the ratio of luminal area to total circumscribed subfoveal choroidal area. Results Fifty-seven eyes with intermediate age-related macular degeneration and 60 healthy control eyes were included in the study. The choroidal vascularity index was computed as 59.53% +/- 4.9% in the intermediate age-related macular degeneration group and as 62.7% +/- 4.3% in the control group (p = 0.002). Patients with age-related macular degeneration showed significantly lower values of stromal area and higher values of luminal area compared to control subjects (0.51 +/- 0.22 vs 0.87 +/- 0.21, p < 0.001 and 0.74 +/- 0.22 vs 0.52 +/- 0.18, p < 0.001, respectively). Conclusion Eyes with intermediate age-related macular degeneration demonstrated reduced choroidal vascularity index compared to healthy eyes. Choroidal vascularity index seems to be a potential non-invasive quantitative method for studying structural changes of the choroid in patients with intermediate age-related macular degeneration.