ObjectiveTo observe the characteristics of choroidal thickness in patients with macular edema secondary to superior temporal branch retinal vein occlusion (BRVO-ME). MethodsA retrospective control study. From November 2020 to September 2021, 30 patients (30 eyes) with BRVO-ME (BRVO-ME group) were diagnosed by ophthalmology examination in Department of Ophthalmology, The Affiliated Hospital of Chengde Medical College and 14 healthy volunteers (28 eyes) were enrolled in the study. The choroidal thickness of macular area was measured by enhanced deep imaging technique of frequency domain optical coherence tomography. According to the subdivision of the diabetic retinopathy treatment group, the choroid within the 6 mm of the macular fovea was divided into three concentric circles with the macular fovea as the center, namely, the central area with the diameter of 1 mm, the inner ring of 1-3 mm and the outer ring of 3-6 mm. The inner ring area and the outer ring area are divided into upper, lower, nasal and temporal sides, respectively, which are denoted as S3, I3, N3, T3 and S6, I6, N6, T6, totaling 9 areas. To observe the distribution characteristics of choroidal thickness in different regions of two groups of eyes. The choroidal thickness of different macular regions was compared by independent sample t-test. ResultsThe choroidal thicknesses in the central area, S3, T3, I3, N3, S6, T6, I6, and N6 of the eyes in the control group and BRVO-ME group were 214.11±56.04, 207.89±57.92, 214.07±54.82, 207.14±61.54, 180.18±53.53, 204.25±59.60, 193.93±51.50, 190.54±51.21, 139.82±39.84 μm and 258.00±71.14, 256.43±68.70, 252.07±72.97, 244.37±68.49, 243.10±70.93, 247.20±68.36, 221.00±61.28, 223.77±58.64, 183.20±60.15 μm. In both groups, the choroidal thickness was the thickest in the central area, gradually thinning to the nasal side and temporal side, and the nasal choroidal thickness was thinner than other regions, and N6 area was the thinnest. Compared with the control group, the choroidal thickness of central area, S3, T3, I3, N3, S6, I6 and N6 in BRVO-ME group were significantly thicker (t=－2.899, －2.229, －2.172,－3.250, －2.543, －2.292, －3.214; P＜0.05), there was no significant difference in T6 area (t=－1.814, P=0.075). ConclusionThe choroidal thickness of macular area in patients with BRVO-ME is thicker than that in normal subjects.