Pattern of association between school grades and myopia: longitudinal findings from the SCORM cohort

Objectives To characterise the pattern of association between school academic performance and myopia shifts among Singaporean children. Methods Children from the Singapore Cohort Study of the Risk Factors for Myopia (SCORM) with available Grade 4 nationwide examination scores and ocular measurements were analysed (n = 721). Cycloplegic refraction and axial length (AL) were assessed at Grade 4 (age 10 years) and Grades 8–10 (aged 14 to 16 years). Multivariable models were used to examine associations between academic performance and annualised changes in spherical equivalent (SE) and AL, accounting for inter-eye correlation, with inclusion of both myopic and non-myopic children at baseline. Results Each 1-SD higher score was associated with a slightly more negative SE change (β = -0.04 D/year; 95% CI -0.062 to -0.011; p = 0.004) and greater axial elongation (β = 0.01 mm/year; 95% CI 0.004 to 0.021; p = 0.003) from Grade 4 to Grades 8–10. Findings were consistent across all subject-specific scores. LOWESS curves suggested possible non-linear patterns, with modestly steeper trends for SE and AL at Grades 8–10 and flatter patterns for their longitudinal changes at the upper end of the score distribution. Conclusions Higher childhood academic performance was associated with faster myopic shift in both myopic and non-myopic children. Exploratory analyses suggested that SE and AL may not be uniformly distributed across the full range of academic performance.