title: Anisometropia in Singapore school children.
abstract: OBJECTIVE
  To report the prevalence rates of anisometropia in a school population and determine the relative contribution of refractive power and axial length to the measured anisometropia.
  
  
  METHODS
  Population-based cross-sectional study.
  
  
  METHODS
  Autorefraction, keratometry, and ultrasonography studies were made.
  
  
  METHODS
  Three schools, located on the eastern, northern, and western part of Singapore.
  
  
  METHODS
  In all, 1,979 children aged 7 to 9 years were recruited for this study. The study sample included Chinese (n = 1,481), Malay (n = 324), and Asian Indian (n = 174) children; 720 subjects have myopia (spherical equivalent <= -0.5 diopters) in at least one eye.
  
  
  METHODS
  Anisometropia.
  
  
  RESULTS
  The prevalence rates of anisometropia, in terms of spherical equivalent (SE) difference of at least 1.5 diopters and 2.0 diopters were 1.57% (95% confidence interval [CI]: 1.1, 2.2) and 1.01% (95% CI: 0.6, 1.6), respectively. The prevalence rate of anisometropia (at least 2.0 diopters) among the children with at least one myopic eye was 2.4% (95% CI: 1.4, 3.8), whereas in those without any myopic eyes, the prevalence rate was only 0.2% (95% CI: 0.06, 0.8). The spherical equivalent difference between the right and left eyes was positively correlated with the difference in axial lengths (P <.001). The difference in corneal refractive power is not statistically different between the anisometropic and the nonanisometropic children.
  
  
  CONCLUSIONS
  The anisometropia prevalence rate in a childhood population with a relatively high prevalence of myopia was reported. The origin of the anisometropia is axial, and these results suggest that the differential rate of elongation between the two eyes of nonmyopic subjects results in anisometropia.
authors.affiliation: Singapore National Eye Center, Singapore, Singapore. Louistong@hotmail.com
authors.forename: Louis
authors.initials: L
authors.lastname: Tong
authors.forename: Seang-Mei
authors.initials: SM
authors.lastname: Saw
authors.forename: Kee-Seng
authors.initials: KS
authors.lastname: Chia
authors.forename: Donald
authors.initials: D
authors.lastname: Tan
mesh_terms: D015858:Anisometropia / Q000175:diagnosis / Q000453:epidemiology*; D002648:Child; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D009216:Myopia / Q000453:epidemiology; D015995:Prevalence; D012574:Schools; D012846:Singapore / Q000453:epidemiology