Objective:To analyze the associations between the choroidal vasculature and submacular fluid (SMF) in central serous chorioretinopathy (CSC).Methods:A retrospective study. A total of 29 CSC patients (31 eyes) with complete records who visited the Department of Ophthalmology in Peking University People's Hospital from August 1, 2021 to March 1, 2023 were included in this study. The patients were divided into complete absorption and incomplete absorption groups according to the status of SMF in the last visit. All the patients underwent ultra-widefield swept-source optical coherence tomography angiography (UWF SS-OCTA) with a scanning range of 24 mm × 20 mm. The UWF SS-OCTA images were automatically analyzed in 9 regions (superotemporal, superior, superonasal, temporal, central, nasal, inferotemporal, inferior, and inferonasal). Alterations of choroidal vasculature in the nine subfields after SMF absorption were described, including choroidal thickness (CT), flow density of choriocapillaris layer, vessel density of large choroidal vessel layer, three-dimensional choroidal vascularity index (CVI), the mean choroidal vessel volume (mCVV), and the mean choroidal stroma volume (mCSV). The relevant factors affecting the complete absorption of SMF were additionally evaluated.Results:At baseline, CT ( Z=2.859, P=0.004), mCVV ( t=2.514, P=0.018), and mCSV ( Z=2.958, P=0.003) in the superotemporal region of the affected eyes in the incomplete absorption group were significantly higher than those in the complete absorption group. Compared with baseline, at the last visit, the proportion of asymmetric vortex veins in the complete absorption group was significantly decreased ( χ2=6.000, P=0.014), CVI in the superotemporal, superonasal, temporal, central, nasal, inferotemporal, and inferonasal regions ( t=-4.125, t=-3.247, Z=-3.213, t=-2.994, t=-3.417, t=-3.733, t=-3.795; P=0.001, 0.006, 0.001, 0.010, 0.005, 0.003, 0.002), the mCVV of 9 regions ( t=-2.959, t=-2.537, t=-2.235, t=-3.260, t=-3.022, t=-2.796, t=-2.747, Z=-2.107, t=-2.935; P=0.011, 0.025, 0.044, 0.006, 0.010, 0.015, 0.017, 0.035, 0.012) were significantly decreased. Compared to the complete absorption group, the choroidal blood flow changes in the non-complete absorption group were more limited, and CT in the upper region increased significantly at the last follow-up ( t=2.272, P=0.037). Multivariate logistic regression analysis revealed that baseline CT in the superotemporal region may be an independent risk factor affecting the complete absorption of SMF (odds ratio=0.981, 95% confidential interval 0.965-0.997, P=0.021). Conclusions:In the process of SMF absorption in CSC, significant reductions of choroidal blood flow were found in the large choroidal vessel layer, and there may be a locally compensatory increase in CT. In addition, baseline CT in superotemporal region is an independent risk factor affecting SMF absorption.

Central serous chorioretinopathy (CSC) is one of the representative pachychoroid spectrum disease. Although fundus fluorescein angiography and indocyanine green angiography can be used as the gold standard for the diagnosis of CSC, they are invasive examinations, which may bring certain risks in clinical application and cannot help us obtain quantitative parameters. Optical coherence tomography angiography (OCTA), as a non-invasive and quantitative examination, is an important imaging tool for understanding the pathogenesis, diagnosis and treatment of CSC. With the advancement of OCTA, the swept-source OCTA has a satisfying scanning depth, a wider scanning range and a higher resolution. The development of OCTA broadens the horizons of the pathogenesis of CSC, promotes the understanding of the pathophysiology of CSC, and sheds new light for its clinical diagnosis and treatment. Based on OCTA, the choroid and retina in eyes with CSC are presented with qualitative and quantitative changes in vascular system. OCTA-guided CSC treatment and the discovery of prognostic markers based on OCTA challenge the application of traditional imaging techniques in CSC. With the continuous improvement and progress of OCTA technology, traditional angiography combined with OCTA will bring great benefits to the diagnosis and treatment of CSC. This review summarizes the quantitative application of OCTA in the pathogenesis, diagnosis and treatment of CSC.

Objective:To evaluate the three-dimensional choroidal vascularity index (3D-CVI) and choriocapillaris blood flow density (CCD) changes in patients with high myopia using ultra-widefield swept-source optical coherence tomography angiography (SS-OCTA), and to investigate the relationship between axial length (AL) and choroidal vascular structure changes in high myopia.Methods:A cross-sectional study was performed.A control group of 168 eyes of 168 normal subjects, and a high myopia group of 182 eyes of 182 high myopia patients were enrolled from November 2021 to October 2022 at the Peking University People's Hospital.All subjects underwent an ultra-widefield SS-OCTA scan with an area of 24 mm × 20 mm.Full-field average and central area 3D-CVI and CCD were compared between the two groups.Correlation analysis and receiver operating characteristic curve analysis were used for 3D-CVI, CCD and AL, respectively.The AL cut-off values were determined when 3D-CVI and CCD were reduced.The study followed the Declaration of Helsinki, and the study protocol was approved by the Ethics Committee of Peking University People's Hospital (No.2021PHB058-001).All participants voluntarily signed an informed consent form.Results:The mean 3D-CVI and central 3D-CVI in the high myopia group were (31.37±7.85)% and (29.63±9.00)%, respectively, which were significantly lower than (32.86±4.25)% and (35.01±3.96)% in the control group ( t=2.241, 7.337; both at P<0.05).The mean CCD in the high myopia group was (45.59±3.63)%, which was significantly lower than (46.47±1.36)% in the control group ( t=3.038, P=0.003).Correlation analysis showed that mean 3D-CVI and CCD were negatively correlated with AL in the high myopia group ( r=-0.547, -0.657; both at P<0.001).Receiver operating characteristic curve analysis of 3D-CVI, CCD and AL suggested that the AL cut-off value of mean 3D-CVI-reduction was 28.93 mm and the area under the curve of 0.883 ( P<0.001, sensitivity=0.690, specificity=0.944).The AL cut-off value of mean CCD-reduction was 28.26 mm and the area under the curve was 0.884 ( P<0.001, sensitivity=0.793, specificity=0.832). Conclusions:3D-CVI and CCD are both reduced in patients with high myopia.As AL increases, CCD changes earlier than 3D-CVI.