Three-dimensional choroidal vascularity index in acute central serous chorioretinopathy using swept-source optical coherence tomography

Purpose To evaluate the three-dimensional choroidal vascularity index (CVI) in the eyes with treatment-naive acute central serous chorioretinopathy (CSC) using swept-source optical coherence tomography (SS OCT). Methods In this prospective cross-sectional study, OCT and OCT angiography covered an area of 12 x 12 mm centered on the fovea. Three-dimensional CVI was defined as the ratio of the choroidal vascular luminal volume to the total choroidal volume. The location of pigment epithelial detachment (PED) and the area with abnormal perfusion at choriocapillary layer were compared with the distribution of the three-dimensional CVI. Results Thirty-two eyes with treatment-naive acute CSC, 18 fellow eyes, and 48 control eyes were enrolled. Three-dimensional CVI had good repeatability on control eyes, with a coefficient of variation of 0.166. The mean CVI in the scan area was 0.35 in the eyes with CSC, 0.34 in the fellow eyes of CSC, and 0.30 in the control eyes. The overall CVI in the control eyes was significantly lower than that in the eyes with CSC and that in fellow eyes (P < 0.001 and P = 0.006, respectively). The eyes with CSC and the fellow eyes had significantly higher CVI values at the posterior pole and the drainage routes of choroidal veins. In the eyes with CSC, PEDs and choriocapillary with abnormal perfusion colocalized with the dilated choroidal vessels, which had high three-dimensional CVI values. Conclusion Increased three-dimensional CVI suggested an increased vascular component in the eyes with CSC and in fellow eyes. The three-dimensional CVI is a useful imaging marker of choroidal diseases that volumetrically assesses the choroidal vasculature and might advance our understanding of CSC pathophysiology.