Purpose: To study the structural changes in the choroid using swept-source (SS) optical coherence tomography (OCT), a tool for the choroidal vascularity index (CVI) following epiretinal membrane removal.
Methods: Fifty-two eyes of 26 patients were evaluated in this prospective, single-centre, observational study. Twenty-six eyes underwent vitrectomy for epiretinal membrane removal (VT-group), and the control group consisted of 26 corresponding fellow eyes (F-group). All patients were evaluated at baseline, 30 and 90 days postsurgery. Using a modified image binarization algorithm for SS-OCT scans, the subfoveal choroidal area was segmented into the luminal and stromal areas, and the CVI was measured by calculating the proportion of the luminal area (LA) to the cross-sectional choroid area.
Results: The mean CVI in the VT-group was 63.86 ± 4.04% at the baseline, 62.45 ± 4.21% at 30 days postsurgery and 61.06 ± 3.79% at 90 days (p < 0.001). The F-group had a mean CVI of 61.12 ± 2.29% at the baseline, 60.91 ± 2.25% at 30 days postsurgery and 61.05 ± 2.28% at 90 days (p = 0.29).
Conclusion: The CVI decreases following epiretinal membrane removal when compared to the fellow eyes, which suggests structural changes in the vascular layers of the choroid. The implication of these results may be that secondary inflammation resulting from mechanical traction induces choroidal thickness by way of increased vascularization of the choroid.
Keywords: choroidal thickness evaluation; choroidal vascular index; optical coherence tomography; vitreomacular surgery.
© 2018 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.