Objective:To observe the correlation between retinal capillary density and retinal thickness in the macula and spherical equivalent (SE) in school-age children.Methods:A cross-sectional study. From May to December 2022, 182 school-age children who visited the ophthalmology department of the First Affiliated Hospital of Zhengzhou University were included. There were 95 males and 87 females. The age ranged from 6 to 12 years, and the spherical equivalent (SE) was +0.50 to -6.00 D. They were divided into three groups based on the SE of the right eyes: 54 eyes in emmetropia group (+0.50≤SE<-0.50 D), 71 eyes in low myopia group (-0.50≤SE<-3.00 D), and 57 eyes in moderate myopia group (-3.00≤SE≤-6.00 D). The macular area of 6 mm×6 mm was scanned using swept-source optical coherence tomography angiography and was divided into three concentric rings centered on the fovea, including the macular central fovea (0-1 mm diameter), inner ring (1-3 mm diameter) and outer ring (3-6 mm diameter). The retinal thickness and blood flow density of superficial vascular plexus (SVP) and deep vascular plexus (DVP) in different zones within 6 mm of the macular area were measured. The relationships between SE and SVP, DVP and retinal thickness in each ring region were investigated by univariate and multivariate linear regression analyses, smooth curve fitting, and threshold effects.Results:There were significant differences in the SVP ( F=6.64, 26.06, 22.69) and DVP ( F=7.97, 25.01, 5.09) of macular central fovea, inner ring and outer ring among the emmetropia, low myopia and moderate myopia groups ( P<0.05). Univariate linear regression analysis showed that the SVP ( β=-0.56,-1.17, -0.79) and DVP ( β=-1.03, -0.93, -0.45) of the three regions were positively correlated with SE ( P<0.05). After smooth curve fitting, threshold effect analysis and multivariate linear regression analysis, the SVP and DVP in the macular central fovea were linearly positively correlated with SE ( β=-0.91, -1.40; P<0.05), and SVP and DVP in the inner ring and outer ring showed an inverted U-shaped curve relationship with SE with the inflection (<3.00 D). When the SE was less than <3.00 D, the SVP and DVP in the inner ring and outer ring were positively correlated with SE ( P<0.05). When the SE was higher than -3.00 D, except for the DVP in the inner ring region, the other parameters were negatively correlated with SE ( P<0.05). There were significant differences in retinal thickness of the inner ring and outer ring ( F=5.47, 16.36; P<0.05), and no significant difference in the macular central fovea among the emmetropia, low and moderate myopia groups ( F=2.16, P>0.05). By using univariate and multivariate linear regression analyses, the retinal thickness in the inner ring and outer ring were negatively correlated with SE ( β =1.99, 3.05; P<0.05). However, no correlation was found between retinal thickness and SE in the macular central fovea ( β=-1.65, P>0.05). Conclusions:In school-age children with SE between +0.50 D and -6.00 D, the retinal capillaries density of the macular central fovea gradually increase, and increase first and then decrease in the inner ring and outer ring with increasing SE. The retinal thickness of inner ring and outer ring gradually decrease and not change significantly in the macular central fovea.

Objective:To evaluate the distribution characteristics of choroidal vascularity index (CVI) in macula among normal children using swept-source optical coherence tomography (SS-OCT), and to investigate the influencing factors.Methods:A cross-sectional study was conducted.Sixty-three children aged 6 to 12 years were enrolled in The First Affiliated Hospital of Zhengzhou University from May 2021 to November 2021.Spherical equivalent refraction, axial length (AL) and other ocular biological parameters were measured.Macula-centered CVI and choroidal thickness (ChT) were measured by SS-OCT angiography.According to the ETDRS partition, the obtained image was divided into macular central fovea (0-1 mm diameter), inner ring (1-3 mm diameter) and outer ring (3-6 mm diameter) zones.Data from the right eye were selected for statistical analysis.CVI in the three rings and four zones (superior, temporal, inferior and nasal zones) of the inner and outer rings were compared.Univariate and multiple linear regression analyses were used to analyze the correlation between CVI and sex, AL, anterior chamber depth (ACD), ChT and pupil diameter.This study adhered to the Declaration of Helsinki.The study protocol was approved by the Ethics Committee of The First Affiliated Hospital of Zhengzhou University (No.2021-KY-0399-003). Written informed consent was obtained from each guardian.Results:The average CVI in the macular central fovea, inner ring and outer ring were 0.35±0.12, 0.32±0.10 and 0.27±0.08, respectively, with a significant difference ( F=10.96, P<0.001), and significant differences in CVI were found in pairwise comparisons of the three ring zones (all at P<0.05). Significant differences in CVI were found among superior, temporal, inferior and nasal zones in inner and outer rings ( Fring=11.60, P=0.001; Fzone=12.02, P<0.05). The CVI was smaller in superior and nasal zones in inner ring than in temporal zone, greater in superior, temporal and inferior zones in outer ring than in nasal zone, smaller in superior zone of outer ring than that of the inner ring, and the differences were statistically significant (all at P<0.001). The single factor linear regression analysis showed that ChT in the fovea, inner ring and outer ring were the influencing factors of CVI in the three ring zones (all at β=0.001, P<0.001). Pupil diameter ( β=0.034, P=0.038; β=0.040, P=0.003; β=0.024, P=0.011) and ACD ( β=0.097, P=0.034; β=0.097, P=0.013; β=0.061, P=0.032) were the influencing factors of CVI in fovea, inner ring and outer ring.After multiple linear regression analysis, the regression equations were established as follows: CVI in the macular fovea=0.001×ChT in the macular fovea + 0.001×ChT in the inner ring+ 0.001×ChT in the outer ring-0.301 ( R2=0.514, F=6.875, P<0.001); CVI in the inner ring=0.001×ChT in the macular fovea+ 0.001×ChT in the inner ring+ 0.001×ChT in the outer ring+ 0.088×AL-0.307 ( R2=0.603, F=9.870, P<0.001); CVI in the outer ring=0.001×ChT in the macular fovea+ 0.001×ChT in the inner ring+ 0.001×ChT in the outer ring-0.135 ( R2=0.601, F=9.781, P<0.001). Conclusions:In children aged 6-12 years old, the CVI is higher in the macular central fovea than in inner and outer rings, and the CVI in nasal zone is the smallest in both inner and outer rings.The thicker the ChT, the higher the CVI in all zones in the macular area; the deeper the anterior chamber, the higher the CVI in the inner ring.