title: Prevalence and association of refractive anisometropia with near work habits among young schoolchildren: The evidence from a population-based study.
abstract: BACKGROUND
  Lifestyle behaviour may play a role in refractive error among children, but the association between near work habits and refractive anisometropia remains unclear.
  
  
  METHODS
  We estimated the prevalence of refractive anisometropia and examined its association with near work activities among 23,114 children in the Myopia Investigation Study in Taipei who were grade 2 elementary school students at baseline in 2013 and 2014. Baseline data on demographics, medical history, parental history and near work habits were collected by parent-administered questionnaire survey. Refractive status was determined by cycloplegic autorefraction. Refractive anisometropia was defined as the spherical equivalent difference ≥ 1.0 diopter between eyes.
  
  
  RESULTS
  The prevalence of refractive anisometropia was 5.3% (95% confidence interval [CI], 5.0% to 5.6%). The prevalence and severity of refractive anisometropia increased with both myopic and hyperopic refractive error. Multivariate logistic regression analysis revealed that refractive anisometropia was significantly associated with myopia (odds ratio [OR], 2.98; 95% CI, 2.53-3.51), hyperopia (OR, 2.37; 95% CI, 1.98-2.83), degree of astigmatism (OR, 1.005; 95% CI, 1.005-1.006), amblyopia (OR, 2.54; 95% CI, 2.06-3.12), male gender (OR, 0.88; 95% CI, 0.78-0.99) and senior high school level of maternal education (OR, 0.69; 95% CI, 0.52-0.92). Though anisometropic children were more likely to spend more time on near work (crude OR, 1.15; 95% CI, 1.02-1.29) and to have less eye-to-object distance in doing near work (crude OR, 1.15; 95% CI, 1.01-1.30), these associations became insignificant after additional adjustment for ocular, demographic and parental factors.
  
  
  CONCLUSIONS
  The present study provides large-scale, population-based evidence showing no independent association between refractive anisometropia and near work habits, though myopia is associated with refractive anisometropia.
authors.affiliation: Department of Ophthalmology, Taipei Veterans General Hospital, Taipei, Taiwan.
authors.forename: Chia-Wei
authors.initials: CW
authors.lastname: Lee
authors.affiliation: Children and Family Research Center, National Taiwan University, Taipei, Taiwan.
authors.forename: Shao-You
authors.initials: SY
authors.lastname: Fang
authors.affiliation: National Yang-Ming University School of Medicine, Taipei, Taiwan.|Department of Ophthalmology, National Yang-Ming University Hospital, Yilan, Taiwan.
authors.forename: Der-Chong
authors.identifier: http://orcid.org/0000-0002-2239-1132
authors.initials: DC
authors.lastname: Tsai
authors.affiliation: Institute of Hospital and Health Care Administration, National Yang-Ming University, Taipei, Taiwan.
authors.forename: Nicole
authors.initials: N
authors.lastname: Huang
authors.affiliation: Department of Ophthalmology, Taipei Veterans General Hospital, Taipei, Taiwan.|Institute of Clinical Medicine, National Yang-Ming University, Taipei, Taiwan.
authors.forename: Chih-Chien
authors.initials: CC
authors.lastname: Hsu
authors.affiliation: Department of Health, Taipei City Government, Taipei, Taiwan.
authors.forename: Shing-Yi
authors.initials: SY
authors.lastname: Chen
authors.affiliation: National Yang-Ming University School of Medicine, Taipei, Taiwan.
authors.forename: Allen Wen-Hsiang
authors.initials: AW
authors.lastname: Chiu
authors.affiliation: Department of Ophthalmology, Taipei Veterans General Hospital, Taipei, Taiwan.|National Yang-Ming University School of Medicine, Taipei, Taiwan.
authors.forename: Catherine Jui-Ling
authors.initials: CJ
authors.lastname: Liu
mesh_terms: D000293:Adolescent; D000550:Amblyopia / Q000150:complications; D015858:Anisometropia / Q000453:epidemiology* / Q000209:etiology*; D002648:Child; D005260:Female; D006184:Habits; D006801:Humans; D008297:Male; D009216:Myopia / Q000150:complications; D011159:Population Surveillance; D015995:Prevalence; D012307:Risk Factors; D012574:Schools; D013334:Students