Purpose. To describe the frequency of and risk factors associated with myop
ia 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-a
dministered questionnaires distributed before the vision screening. These f
actors 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. Result
s suggest that the prevalence of myopia in 6-year-old children is associate
d with both hereditary and nonhereditary factors. In accord with prior work
, the results argue that low birth weight has a permanent influence upon: e
ye development.