Factors Associated with the Prevalence of Myopia in 6-Year-Olds

PURPOSE: To describe the frequency of and risk factors associated with myopia in grade one children. METHODS: Refractive error was measured by static retinoscopy, without cycloplegia, for 10,616 children in the first year of a province-wide vision-screening program. Information on factors that might be associated with myopia was collected from parents or guardians by self-administered questionnaires distributed before the vision screening. These factors were evaluated by a case-control method. RESULTS: The prevalence of myopia, greater than -0.25 D, was 6%. The estimated relative risk of myopia was increased significantly among children whose birth weight was <2500 g and whose mothers had a history of early spectacle use. CONCLUSIONS: Results suggest that the prevalence of myopia in 6-year-old children is associated with both hereditary and nonhereditary factors. In accord with prior work, the results argue that low birth weight has a permanent influence upon eye development.