ABSTRACT [Download PDF] [Read Full Text]
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.