ObjectiveTo investigate macular microvascular abnormalities in eyes with subfoveal fibrotic nodules secondary to Coats' disease. MethodsA cross-sectional study. From January 1, 2018 to July 30, 2021, 45 eyes of 45 patients diagnosed with Coats' disease with or without subfoveal fibrotic nodules in Eye and ENT Hospital, Shanghai Medical College of Fudan University were included in this study. There were 40 eyes in 40 males and 5 eyes in 5 females. All were under 21 years old. According to the presence or absence of subfoveal fiber nodules, the patients were divided into fibrotic group (26 cases, 26 eyes) and non-fibrotic group (19 cases, 19 eyes). Optical coherence tomography angiography was used to scan 3 mm×3 mm or 6 mm×6 mm macular area of both eyes. The software of the device automatically processed the images. The presence of FAZ edge anastomotic vascular arch ring breakage and abnormal microvascular branch (AMB) in the foveal avascular zone (FAZ) were observed. ResultsIn 26 eyes of fibrosis group, AMB originating from the parafoveal retinal capillary network was observed, which grew into and destroyed the integrity of the vascular arch ring at the edge of FAZ. AMB was crisscrossing and winding, and its curvature expands. B-scan images showed the blood flow signal in the subfoveal fiber nodule, and the blood flow signal traversed between the inner retina and the fiber nodule in 23 eyes (88.46%, 23/26). In the non-fibrosis group, all the vascular abnormalities were characterized by capillary dilation and defect, and no breakage of FAZ anastomotic vascular arch ring or AMB was observed. ConclusionsIn Coats' disease with subfoveal fiber nodules, staggered and dilated AMBs emerge from the parafoveal vascular network, grow into and destroy the integrity of the vascular arch ring at the edge of FAZ, and grow down longitudinally into the fiber nodules.