background

Childhood is an important stage for the occurrence and development of myopia. Less population-based studies have been performed to focus on the factors associated with longer AL and myopia among children.

objective

This study aims to explore the prevalence of myopia, axial length (AL), and associated factors among children and adolescents aged 4 to 18 years in Beijing. The findings are expected to provide a scientific basis for taking effective measures to prevent and control myopia for government decision-making.

methods

This cross-sectional survey involved 2595 children from 9 randomly selected educational institutions (1 kindergarten and 8 schools) in a big municipality. The survey included a questionnaire, visual acuity examination, refractive screening, and axial length measurement.

results

The prevalence of myopia among the tested students was 56.53%, and 50.98% of students had a longer AL (AL>23.5mm and naked eye vision of <5.0). There were statistically significant differences in myopia prevalence rates between different sexes (male 52.71% vs female 60.23%, χ2=14.93, P < 0.001) and different school⁃age groups (7.73%, 36.12%, 58.26%, 69.05%, χ2= 348.24, P < 0.001). The AL is elongated with age, and the right was longer than the left (t=2.22, P<0.05). Excluding preschool children, the AL was significantly different between students with and without myopia (t=23.86, P<0.05). The univariate analysis showed significant differences in the myopia rates by age, sex, long distance reading time on electrics, close distance learning time, reading distance, children know the 20 rules, learning lighting, father with myopia and mother with myopia (χ2=348.24, 14.93, 6.85, 11.86, 5.42, 7.22, 8.21, 12.56,7.89, all P<0.05). The univariate analysis showed significant differences in the rate of longer AL by age, long distance reading time on electrics, close distance learning time, reading distance, children know the 20 rules, learning lighting, father with myopia and mother with myopia (χ2=360.79, 11.84, 11.73, 4.74, 5.42, 5.93, 9.92, 21.71,10.55, all P<0.05).The multivariable logistic analysis showed that older children was risk factors for myopia and longer AL (OR=1.27, 95% CI=1.23–1.30; OR= 1.31, 95% CI=1.27–1.35), with girls being more likely to develop myopia than boys (OR, 1.35; 95% confidence interval, 1.13–1.60).And myopia in mother was risk factors for myopia and longer AL (OR= 0.67, 95% CI=0.56–0.80; OR= 0.64, 95% CI=0.53–0.76), myopia in father was risk factors for myopia and longer AL (OR= 0.76, 95% CI=0.63–0.93; OR= 0.68, 95% CI=0.56–0.82).

conclusions

The prevalence of myopia and the proportion of longer AL were high in children and adolescents aged 4 to 18 years. Therefore, it is possible to predict the occurrence and development of myopia in children by measuring the AL and to prevent and control myopia in children and adolescents by reducing the near work on reading time and maintaining an adequate reading distance.

clinicaltrial