Macular microvascular remodeling in non-pathological high myopia revealed by optical coherence tomography angiography

PURPOSE: To characterize subclinical macular microvascular alterations in eyes with high myopia (HM) using optical coherence tomography angiography (OCTA) and to investigate the relationship between retinal microvasculature, retinal thickness (RT), and axial length (AL). METHODS: In this prospective, cross-sectional study, 108 eyes with HM (spherical equivalent ≤ -6.00 D, axial length ≥ 26 mm) and 96 age- and sex-matched healthy control eyes were examined. Macular vascular density (VD) in the superficial and deep capillary plexuses (SCP and DCP), foveal avascular zone (FAZ) metrics, and RT were quantified after ocular magnification correction. Correlations between OCTA parameters, RT, and AL were evaluated using Pearson's correlation analysis. RESULTS: In both SCP and DCP, foveal VD was significantly higher in HM eyes compared with controls (P < 0.001), whereas parafoveal VD was markedly reduced (P < 0.001). FAZ area and perimeter were significantly enlarged in HM eyes (P = 0.01 and P = 0.02, respectively). The foveal RT was significantly higher in the HM group compared with controls (P < 0.001). In contrast, the parafoveal RT was significantly lower in the HM group compared with controls (P < 0.001). Correlation analysis revealed that VD was positively associated with regional RT in the HM group (all P < 0.01). Notably, while AL showed a negative association with parafoveal VD and a positive correlation with FAZ metrics, no significant correlation was observed between AL and foveal VD in the HM group. CONCLUSIONS: Eyes with HM without pathological changes exhibit a distinct pattern of macular microvascular remodeling, characterized by reduced parafoveal VD alongside increased foveal VD. These findings suggest that microvascular attenuation is more pronounced in the parafoveal region than in the foveal center and highlight OCTA-derived vascular metrics as candidate imaging features for characterizing non-pathological HM, which warrant validation in longitudinal studies.