Assessment of artifact-removed choriocapillaris flow voids in eyes with pachychoroid spectrum disorders

Abstract

Purpose: To compare choriocapillaris flow voids in pachychoroid spectrum disorders with an optical coherence tomography angiography (OCTA) image processing strategy excluding artifacts. Study design: Retrospective case-control study. Methods: This study included 22 eyes with pachychoroid pigment epitheliopathy (PPE), 25 with spontaneously resolved central serous chorioretinopathy (CSC), 20 with photodynamic therapy (PDT)-treated CSC, 21 with active CSC, 19 with pachychoroid neovasculopathy (PNV) and 24 healthy eyes. The number, average area, and maximum area of flow voids and the percentage of nonperfused choriocapillaris area (PNPCA) were evaluated on artifact-removed binarized OCTA images using a custom MATLAB-powered algorithm. Results: The PNV group had the largest flow void maximum area, flow void average area, and PNPCA. After adjusting for covariates, PPE, active-CSC, and PNV were associated with increased PNPCA and with increases across all choriocapillaris flow-void parameters, whereas PDT-CSC was associated only with a larger maximum flow-void area. In pairwise comparisons, PNV showed a greater maximum flow-void area than other groups, and PNV had a higher average flow-void area than controls and spontaneously resolved CSC (p < 0.05). Pairwise comparisons showed no significant differences in the number of flow voids among the groups. The location of the maximum flow-void area was consistent with the location of pachyvessels (80%) and choroidal neovascularization (84.2%). Conclusions: Flow void parameters have higher values in pachychoroid eyes than in healthy controls. These parameters are worst in eyes with PNV. The maximum area of the choriocapillaris flow void, especially, may be a marker of focal ischemia and the tendency to development of PNV.