Exploring the Relationship Between Multilayered Choroidal Neovascularization and Choriocapillaris Flow Deficits in AMD

Purpose We used optical coherence tomography angiography to test the hypothesis that more complex, multilayered choroidal neovascular (CNV) membranes in AMD are associated with worse flow deficits (FD) in the choriocapillaris. Methods Retrospective, cross-sectional study including 29 eyes of 29 subjects with neovascular AMD. En face choriocapillaris images were compensated for signal attenuation using the structural OCT slab and signal normalization based on a cohort of healthy subjects. We binarized the choriocapillaris using both local Phansalkar and global MinError(I) methods and quantified FD count, FD density, and mean FD size in the entire area outside the CNV, in the 200-µm annulus surrounding the CNV, and in the area outside the annulus. We used projection-resolved optical coherence tomography angiography to quantify CNV complexity, including highest CNV flow height, number of flow layers, and flow layer thickness. We explored the relationship between CNV complexity and choriocapillaris FD using Spearman correlations. Results The highest CNV flow signal significantly correlated with lower FD count (P < 0.01), higher FD density (P < 0.05), and higher mean FD size (P < 0.05) in the area outside the annulus and the entire area outside the CNV using both Phansalkar and MinError(I). Within the annulus, CNV complexity was not consistently correlated with choriocapillaris defects. Conclusions CNV vascular complexity is correlated with choriocapillaris FD outside the CNV area, providing evidence for the importance of choriocapillaris dysfunction in neovascular AMD, as well as the potential role of choroidal ischemia in the pathogenesis of complex CNV membranes.