The associations of high academic performance with childhood ametropia prevalence and myopia development in China

Abstract

Background: To assess associations of high academic performance with ametropia prevalence and myopia development in Chinese schoolchildren.

Methods: This multicohort observational study was performed in Guangdong, China. We first performed a cross-sectional cohort analysis of students in grades 1 to 9 from Yangjiang to evaluate the relationship between academic performance and refractive status on a yearly basis. We also performed longitudinal analyses of students in Shenzhen to evaluate the trend of academic performance with refractive changes over a period of 33 months. All refractive statuses were measured using noncycloplegic autorefractors.

Results: A total of 32,360 children with or without myopia were recruited in this study (mean age 10.08 years, 18,360 males and 14,000 females). Cross-sectional cohort analyses in Yangjiang showed that the prevalence of hyperopia was associated with lower academic scores in grade one, the year students entered primary school (β=-0.04, P=0.01), whereas the prevalence of myopia was associated with higher academic scores in grade six and grade eight, the years in which students were about to take entrance examinations for junior high school or senior high school (β=0.020, P=0.038; β=0.041, P=0.002). Longitudinal analysis showed that in Shenzhen, faster myopia development was associated with better scores in all grades even after adjustments for BMI, outdoor activity time, screen time, reading time, and parental myopia (grade two at baseline: β=0.026, P<0.001; grade three at baseline: β=0.036, P=0.001; grade four at baseline: β=0.014, P<0.001; grade five at baseline: β=0.039, P<0.001; grade six at baseline: β=0.04, P<0.001).

Conclusions: Refractive errors correlated significantly with academic performance among schoolchildren in China. Children with high academic performance were more likely to have faster myopia development.

Keywords: Refractive error; academic performance; cohort study; hyperopia; myopia.

Figure 1

Analyses of the proportions and trends of refractive error stratified by gender. (A) From grade one to grade nine, the prevalence of hyperopia decreased (from 6.4% to 0%, χ²=45.03, P<0.001). (B) The prevalence of myopia increased (from 10.4% to 89.4%, χ²=1,020.00, P<0.001), and the growth rate peaked from grades six to seven (from 58.7% to 78.8%). (C) The proportion of each category of myopia increased from grades one to nine (low myopia, χ²=245.95, P<0.001; moderate myopia, χ²=1,056.86, P<0.001; high myopia, χ²=465.22, P<0.001). Compared to the males, the females had a higher prevalence of myopia (χ²=20.06, P<0.001) but a comparable prevalence of hyperopia (χ²=0.08, P=0.78).

Figure 2

Scatter plots of the association between academic performance and the presence of myopia according to the cross-sectional analyses. In grade six and grade eight, myopia was significantly correlated with a better academic outcome (β=0.020, P=0.038; β=0.041, P=0.002). We converted the total score and the scores of each subject to scores on a 0–100% grading scale for statistical analysis.

Figure 3

Scatter plots of the association between academic performance and refractive changes according to the longitudinal analyses. As myopia developed, a faster refraction change was observed to be associated with better academic performance among students in all grades. We converted the total score and the scores of each subject to scores on a 0–100% grading scale for statistical analysis.