title: Factors associated with the prevalence of myopia in 6-year-olds.
abstract: OBJECTIVE
  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.
authors.affiliation: School of Optometry, University of Waterloo, Ontario, Canada.
authors.forename: B E
authors.initials: BE
authors.lastname: Robinson
mesh_terms: D000367:Age Factors; D002648:Child; D005260:Female; D006801:Humans; D007230:Infant, Low Birth Weight; D007231:Infant, Newborn; D008297:Male; D018811:Maternal Exposure / Q000009:adverse effects; D009216:Myopia / Q000175:diagnosis / Q000453:epidemiology* / Q000209:etiology; D016017:Odds Ratio; D009864:Ontario / Q000453:epidemiology; D011247:Pregnancy; D015995:Prevalence; D012029:Refraction, Ocular; D012189:Retrospective Studies; D012307:Risk Factors; D011795:Surveys and Questionnaires