Purpose This study aimed to compare the choroidal vascularity index (CVI) of eyes having Fuchs' uveitis syndrome (FUS) with healthy fellow eyes (N). Methods This prospective, cross-sectional study included unilateral FUS cases and an age- and gender-matched healthy control group. Thirty-nine participants were included in the FUS group, and 24 age- and gender-matched individuals were randomly selected for the control group. Endothelial cell density (ECD) was measured using Tomey specular microscopy. Spectral-domain optical coherence tomography was used to acquire the choroidal images, and binarization was applied to the images. Two blinded investigators analyzed the CVI in both eyes of the FUS cases and the right eyes of the healthy control group. Results CVI was found to be significantly decreased in FUS (p < 0.001). Additionally, ECD had a strong positive correlation with CVI (r = 0.383, p = 0.008). Conclusion CVI may provide information about the chronicity of the disease.