ObjectiveTo measure and analyze the oxygen saturation and retinal blood vessel diameter in the eyes of patients with convalescence Vogt-Koyanagi-Harada (VKH) syndrome. MethodsIn this cross-sectional study, 28 eyes of 14 patients with convalescence VKH syndrome (VKH group) and 20 eyes of 10 healthy subjects (control group) were enrolled. The oxygen saturation and retinal blood vessel diameter were detected by spectrophotometric oximetry unit. Retinal images were collected using filters with wavelengths of 570 nm and 600 nm in the darkroom by the same technologist and then the fused image was obtained. The oxygen saturation of retinal vessels was marked in different colors. The measurement was repeated 2-3 times for each patient, then take an average. A top-quality image in each eye was selected to detect the oxygen saturation and diameter of retinal vessel which located in 1.5-3.0 disc diameter from the optic disc. Image analysis and data acquisition were completed by another technologist. ResultsRetinal venous oxygen saturation was (54.34±8.05)% in the VKH group and (60.07±7.91)% in the control group. The former was lower than the latter, the difference was significant (t=2.443, P=0.017). The mean diameter of retinal arteries was (102.8±18.1) μm in the VKH group and (112.9±19.8) μm in the control group. The former was smaller than the latter, the difference was significant (t=2.406, P=0.018). There was no significant difference of the mean diameter of retinal veins, oxygen saturation of retinal arteries and the arterial-venous difference between two groups (t=-0.330, 0.804, -0.631; P=0.743, 0.403, 0.536). ConclusionsRetinal venous oxygen saturation and the mean diameter of retinal arteries are significantly decreased in patients with VKH syndrome. There is no significant difference of diameter of retinal veins, oxygen saturation of retinal arteries and the arterial-venous difference between VKH syndrome patients and healthy subjects.