Long-term Reproducibility of Optical Coherence Tomography Angiography Parameters in Patients with High Myopia

Purpose: To evaluate the long-term reproducibility of OCTA parameters in patients with high myopia.Design: Retrospective study. Subjects:Patients with high myopia and normal controls.Methods: Subjects were divided into two groups: patients with high myopia (HM group) and normal controls (Control group).Measurements of foveal avascular zone (FAZ) area, vessel density (VD) of superficial vascular complex (SVD), deep vascular complex (DVD), and choriocapillaris (CVD) were analyzed three times at 6-month intervals.Intraclass correlation coefficient (ICC) and coefficient of variation (CV) values were calculated.Main Outcome Measures: ICC and CV of SVD, DVD, and CVD.Results: A total of 194 eyes were enrolled: 99 in the HM group and 95 controls.In the HM group, the ICC/CV of FAZ area were 0.783/20.8%,versus 0.931/9.5% in controls.For SVD, values were 0.636/15.9% in HM group and 0.827/9.7% in controls; for DVD, 0.590/15.7%and 0.731/9.8%;for CVD, 0.672/9.8%and 0.842/7.2%,respectively.In linear regression analysis, image quality was associated with the CV of SVD (B = -1.38,P = 0.004) and DVD (B = -1.86,P = 0.004).For CVD, multivariable analysis showed that axial length (B = 1.93,P < 0.001) and image quality (B = -1.13,P = 0.004) were significantly associated with the CV.Conclusions: Reproducibility of the FAZ area was relatively good, while SVD and CVD were moderate and DVD the poorest in high myopia.OCTA image quality had a significant impact on the long-term reproducibility of vessel density in all layers.