Three-Dimensional Choroidal Vessels Assessment in Fellow Eyes of Patients With Central Serous Chorioretinopathy.

Purpose: To evaluate choroidal vasculature using a novel three-dimensional algorithm in fellow eyes of patients with unilateral chronic central serous chorioretinopathy (cCSC). Methods: Patients with unilateral cCSC were retrospectively included. Automated choroidal segmentation was conducted using a deep-learning ResUNet model. Phansalkar thresholding was applied to binarize choroidal vasculature, and three-dimensional maps were created. Mean choroidal vessel diameter, intervessel distance, choroidal thickness, and choroidal vascularity index (CVI) were measured. Linear mixed models were used for statistical analysis. Results: Thirty unilateral cCSC eyes, 22 fellow, and 26 controls were included. Both cCSC and fellow eyes exhibited significant higher mean choroidal vessel diameter compared with controls (362.50 ± 83.23 µm, 276.84 ± 26.89 µm, and 233.28 ± 28.18 µm, respectively; P < 0.001), and in choroidal thickness (288.90 ± 64.77 µm, 269.76 ± 71.17 µm, and 223.97 ± 43.40 µm, respectively; P = 0.001). The intervessel distance was reduced in cCSC and fellow eyes compared with controls (196.53 ± 23.58 µm, 225.05 ± 33.72 µm, and 264.13 ± 46.06 µm, respectively; P < 0.001). Although lower, the CVI was not significantly different in cCSC and fellow eyes compared with controls (38.14 ± 5.55%, 37.23 ± 6.41%, and 40.65 ± 3.53%, respectively; P = 0.066), indicating a possible trend toward a lower CVI. Conclusions: Three-dimensional representation of choroidal vasculature revealed significant changes in both cCSC and fellow eyes, including a larger diameter and reduced spacing compared with healthy controls. Translational Relevance: Using a validated deep learning-based three-dimensional method, we observed changes in the choroidal vasculature in both CSC and fellow eyes.