Temporal variations in myopia progression in Singaporean children within an academic year

Purpose: Excessive nearwork is believed to be associated with myopia develo pment and progression. To investigate this further, we studied refractive e rror changes and their correlation with nearwork in a cohort of grade schoo l children in Singapore. Methods: Cycloplegic autorefraction was performed 5 times over 10 months on 168 children aged 7, 9, and 12 years who were fur ther divided into myopic and nonmyopic subgroups based in their initial ref ractive errors. Information about nearwork was obtained through diaries fil led out over 24 h at the commencement of the study. Results: Myopia progres sion was high (overall mean: -0.87 D per year) and largely linear throughou t the year, but significantly higher rates were seen after the final school examinations in 7-year-old myopes and nonmyopes. Overall, myopic groups ex hibited higher progression rates than nonmyopic groups, although 33.6% of s ubjects from the latter groups had become myopic by the end of the study. N earwork scores derived from the diaries were generally not well correlated with overall myopia progression. Conclusions: The tendency for myopia progr ession rates to increase after the final school examinations in 7-year-olds is interpreted as a delayed effect of the intense nearwork associated with preparing for them. The timing of nearwork-diary data collection at the be ginning of the study could be responsible for the poor correlation between these data and overall myopia progression rates.