title: Prevalence of anisometropia in Taiwanese schoolchildren.
abstract: OBJECTIVE
  This study investigated the prevalence and distribution of anisometropia in Taiwanese schoolchildren using nationwide data from refractive surveys performed in 1995 and 2000.
  
  
  METHODS
  Complete survey data was obtained for 11,175 students in 1995 and 10,878 students in 2000. The refractive status of each student was measured using an autorefractometer under cycloplegia and rechecked with retinoscopy. The difference in refractive status between each participant's eyes was determined. Chi-squared statistic was used to assess the difference between the 2 surveys. Multiple linear regression was used to determine the trend and effects of covariates.
  
  
  RESULTS
  Most of the schoolchildren (77.6% in 1995, 71.9% in 2000) were not anisometropic. Most of the anisometropic differences were in the range 0.5 to 1.0 D (14.1% in 1995 vs 17.9% in 2000). About 6% of schoolchildren in 1995 and 7.0% in 2000 had anisometropic differences in the range from -1.0 to -2.0 D. Fewer than 4% of students had a level of anisometropia greater than 2.0 D (2.7% vs 3.2%, respectively). The prevalence of anisometropia and the extent of anisometropic difference both increased with age and with maximal myopic refraction (both p < 0.0001). Both the prevalence and extent of anisometropia showed significant differences between the 2 surveys (both p < 0.0001).
  
  
  CONCLUSIONS
  Most of the Taiwanese schoolchildren surveyed were non-anisometropic. The prevalence and amount of anisometropia were significantly increased from 1995 to 2000. The mechanisms responsible for these increases have not been determined, but may be related to increase of myopic refraction.
authors.affiliation: Department of Ophthalmology, College of Medicine, National Taiwan University, Taipei, Taiwan.
authors.forename: Yung-Feng
authors.initials: YF
authors.lastname: Shih
authors.forename: Chu Hsing Kate
authors.initials: CH
authors.lastname: Hsiao
authors.forename: Shu-Hui
authors.initials: SH
authors.lastname: Wen
authors.forename: Luke Long-Kuang
authors.initials: LL
authors.lastname: Lin
authors.forename: Chien-Jen
authors.initials: CJ
authors.lastname: Chen
authors.forename: Por-Tying
authors.initials: PT
authors.lastname: Hung
mesh_terms: D000293:Adolescent; D000367:Age Factors; D015858:Anisometropia / Q000453:epidemiology*; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D015995:Prevalence; D012044:Regression Analysis; D013624:Taiwan / Q000453:epidemiology; D013997:Time Factors