title: Anisometropia prevalence in a highly astigmatic school-aged population.
abstract: OBJECTIVE
  To describe prevalence of anisometropia, defined in terms of both sphere and cylinder, examined cross-sectionally, in school-aged members of a Native American tribe with a high prevalence of astigmatism.
  
  
  METHODS
  Cycloplegic autorefraction measurements, confirmed by retinoscopy and, when possible, by subjective refraction were obtained from 1041 Tohono O'odham children, 4 to 13 years of age.
  
  
  RESULTS
  Astigmatism > or =1.00 diopter (D) was present in one or both eyes of 462 children (44.4%). Anisometropia > or =1.00 D spherical equivalent (SE) was found in 70 children (6.7%), and anisometropia > or =1.00 D cylinder was found in 156 children (15.0%). Prevalence of anisometropia did not vary significantly with age or gender. Overall prevalence of significant anisometropia was 18.1% for a difference between eyes > or =1.00 D SE or cylinder. Vector analysis of between-eye differences showed a prevalence of significant anisometropia of 25.3% for one type of vector notation (difference between eyes > or =1.00 D for M and/or > or =0.50 D for J0 or J45), and 16.2% for a second type of vector notation (between-eye vector dioptric difference > or =1.41).
  
  
  CONCLUSIONS
  Prevalence of SE anisometropia is similar to that reported for other school-aged populations. However, prevalence of astigmatic anisometropia is higher than that reported for other school-aged populations.
authors.affiliation: Department of Ophthalmology and Vision Science, The University of Arizona, Tucson, AZ 85711, USA. vdobson@eyes.arizona.edu
authors.forename: Velma
authors.initials: V
authors.lastname: Dobson
authors.forename: Erin M
authors.initials: EM
authors.lastname: Harvey
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Miller
authors.forename: Candice E
authors.initials: CE
authors.lastname: Clifford-Donaldson
mesh_terms: D000293:Adolescent; D017677:Age Distribution; D015858:Anisometropia / Q000208:ethnology*; D001130:Arizona / Q000453:epidemiology; D001251:Astigmatism / Q000208:ethnology*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007198:Indians, North American / Q000706:statistics & numerical data*; D008297:Male; D015995:Prevalence; D012029:Refraction, Ocular; D042262:Retinoscopy; D017678:Sex Distribution