Comparison of macular vascular density and retinal thickness in children with different degrees of myopia

AIM: To observe and compare the changes of macular vascular density and retinal thickness in children and adolescents with different degrees using optical coherence tomography angiography(OCTA), then analyze their correlation.METHODS: Our prospective cross-sectional study included 230 eyes of 115 children and adolescents aged 6-18a. According to spherical equivalent power(SE), they were divided into four groups: emmetropia group(32 eyes of 16 cases), mild myopia group(94 eyes of 47 cases), moderate myopia group(68 eyes of 34 cases), and high myopia group(36 eyes of 18 cases). Using RTVue XR scans of the 6mm×6mm region of the macula, the system automatically divided it into three rings: 1mm(fovea)ring, 1mm-3mm(parafovea)ring, and 3mm-6mm(perifovea)ring. And each ring was further divided into four quadrants: temporal(T), superior(S), nasal(N), and inferior(I). Quantitatively analysis was performed for the superficial and deep capillary densities and retinal thickness of each sector.RESULTS: The superficial capillary density in the macula was in turn significantly decreased as in emmetropia(44.4±3.5)%, mild myopia(44.8±3.8)%, moderate myopia(44.3±3.8)%, and high myopia(42.6±4.5)% groups(F=2.963,P=0.033). The superficial capillary density of parafovea's temporal side were(46.1±3.5)%,(46.8±5.1)%,(46.2±4.3)%, and(43.8±5.5)% in the four groups, respectively(F=3.436, P=0.018). Similarly, the deep capillary density of the four groups was(49.9±4.1)%,(48.4±4.7)%,(47.9±5.5)%, and(45.3±4.7)%, respectively(F=4.806, P=0.003). The deep capillary density of the perifovea was(49±4.4)%,(47.2±5.2)%,(46.6±6)%, and(43.6±5.1)% in the 4 groups, respectively(F=5.495, P=0.001). The retinal thickness of the four groups was 293.9±12.9, 295.5±13.0, 290.9±12.0, and 284.5±10.7 μm(F=6.606, P<0.001). The superficial capillary densities of parafoveal's temporal and nasal sides were positively correlated with SE(r=0.221, 0.219, P=0.001, 0.001). The deep capillary density of perifovea's temporal, superior, nasal and inferior side were positively correlated with SE(r=0.172, 0.200, 0.250, 0.296, P=0.011, 0.003, <0.001, <0.001). The central retinal thickness except the fovea were positively correlated with SE(P<0.05).CONCLUSION: With the increase of myopia degree of children and adolescents, the superficial capillaries density in the macula decreases, especially in the parafovea's temporal side; as well as the deep capillaries density, especially decreases in the perifovea. The central retinal thickness decreases in both parafovea and perifovea. With the myopia degree of children and adolescents increases, the structure and capillary circulation of the macula will be influenced, especially in the high myopia group.