ObjectiveTo compare the choriocapillaris flow density and choroidal vessel volume (CVV) of acute and chronic central serous chorioretinopathy (CSC).MethodsA cross-sectional observational clinical study. A total of 64 eyes of 64 patients (CSC group) diagnosed with CSC at Department of Ophthalmology of West China Hospital of Sichuan University from May 2019 to October 2020, and a total of 64 eyes of 64 age and gender matched healthy volunteers (control group) during the same period were included in this study. In the CSC group, there were 34 patients with acute CSC (acute CSC group) and 30 patients with chronic CSC (chronic CSC group). There was no significant difference in age (t=－0.041) and sex composition ratio (χ2=0.191) between CSC group and control group (P＞0.05). There were statistically significant differences in age (t=－1.872) and sex composition ratio (χ2=8.778) between acute CSC group and chronic CSC group (P＜0.05). Swept source optical coherence tomography angiography (SS-OCTA) was performed using VG200D. The scanning mode was 512×512 and scannig range was 12 mm × 12 mm. The choriocapillaris flow density of the 3 mm, 6 mm, 12 mm circular area and 1-3 mm ring, 3-6 mm ring, and 6-12 mm ring, and the CVV of the of the 3 mm, 6 mm, 12 mm circular area was automatically generated by the built-in software (v1.28.6). The age, choriocapillaris flow density and CVV were compared between two groups using independent sample t test.ResultsCompared with the control group, the choriocapillaris flow density decreased in the CSC group, and there were statistically significant differences in the 3 mm, 6 mm circular area (t=－7.210, －4.040; P＜0.001). There were statistically significant differences between CSC group and control group in the 3 mm, 6 mm, 12 mm circular area (t=1.460, 12.270, 11.250; P＜0.05). Compared with the acute CSC group, the choriocapillaris flow density decreased in the chronic CSC group, and there were statistically significant differences (P＜0.05) in the 3 mm, 6 mm circular area (t=3.230, 2.330), the total and four quadrants of 1-3 mm ring (t=2.780, 2.060, 2.140, 2.620, 3.770), the superior quadrants of the 3-6 mm ring (t=2.550), and the superior and temporal of 6-12 mm ring (t=3.070, 2.610). There was no significant difference of CVV in the 3 mm, 6 mm and 12 mm circular area between the acute CSC group and the chronic CSC group (t=0.250, 0.070, －0.110; P＞0.05).ConclusionCompared with acute CSC, chronic CSC exhibits significant decreased choriocapillaris flow density and no change in CVV.