Changes in macular vascular density and retinal thickness in young myopic adults without pathological changes: an OCTA study.

The aim of the study was to quantify the macular vascular density and retinal thickness in the eyes of young myopic people with myopia without pathological changes using optical coherence tomography angiography (OCTA).In this cross-sectional study, 160 eyes of 80 myopia subjects without pathological changes were classified into three groups: mild myopia (N=40 eyes), moderate myopia (N=66 eyes), and high myopia (N=54 eyes). Macular vascular density (VD), retinal thickness, area of the foveal avascular zone, the flow area of the outer retina and choriocapillaris (CC) were measured using OCTA. The effects of other confounding factors including axial length, the spherical equivalent, and some systemic factors (blood pressure, height, weight, etc.) were also considered.As the severity of myopia increases, the CC flow area decreased (p=0.029). The superficial VD in the temporal, superior, nasal, and inferior regions was significantly lower in high myopia group compared to moderate and low myopia groups (all p<0.001). With increasing myopia, a significant reduction of deep VD was found in the superior region of the macula (p=0.007). In the fovea, there was no difference in the superficial or deep VD across groups (p=0.268 and p=0.413, respectively). Parafoveal retinal thickness was thinnest in the high myopia group and thickest in the mild myopia group (all p<0.05). The fovea was thickest in the high myopia group and thinnest in the mild myopia group (p=0.030).In young myopic people without pathological changes, superficial VD and retinal thickness decreased with myopia progression, except in the fovea. The CC flow area decreased with increasing myopia.