title: Study design, rationale and methods for a population-based study of myopia in schoolchildren: the Myopia Investigation study in Taipei.
abstract: BACKGROUND
  To describe the study design, rationale and methodology of the Myopia Investigation Study in Taipei (MIT).
  
  
  METHODS
  The MIT was a city-wide, population-based cohort study.
  
  
  METHODS
  Participants were grade 2 students (Fall 2013) of all 153 elementary schools in Taipei City.
  
  
  METHODS
  The baseline data on the risk factors for myopia development was collected by parent-administered questionnaire surveys covering demographics, medical history, parental myopia, time spent on near work and outdoor activities, reading habits and eye care-seeking behaviour. Ocular examinations focused on the measurement of visual acuity (unaided and best-corrected) and refractive status (before and after cycloplegia), which will be carried out for the eligible schoolchildren biannually for 3 years consecutively. Once myopic children are identified, case manager-led telecoaching for health-care instructions and reminders will be delivered to parents or caregivers.
  
  
  METHODS
  To build a comprehensive database for prevalence, incidence and risk factors of early childhood myopia over a 3-year follow-up period.
  
  
  RESULTS
  Of all 19 374 eight-year-old schoolchildren (10 210 [52.7%] boys) eligible for the MIT, 16 486 (85.1%) responded to the questionnaire, 12 019 (62.0%) were examined during the third quarter of 2013 and 11 590 (59.8%) (6267 [52.9%] boys) completed cycloplegic autorefraction on both eyes and were enrolled for further data analysis. There was no significant difference in terms of demographics between the analysed participants and all grade 2 students in Taipei City.
  
  
  CONCLUSIONS
  Data from the MIT will provide population-based information concerning the prevalence, incidence and risk factors for myopia development among young schoolchildren in a metropolitan area of Taiwan.
authors.affiliation: School of Medicine, National Yang-Ming University, Taipei, Taiwan.|Department of Ophthalmology, National Yang-Ming University Hospital, Yilan, Taiwan.
authors.forename: Der-Chong
authors.initials: DC
authors.lastname: Tsai
authors.affiliation: Department of Health, Taipei City Government, Taipei, Taiwan.
authors.forename: Li-Ju
authors.initials: LJ
authors.lastname: Lin
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: Institute of Clinical Medicine, National Yang-Ming University, Taipei, Taiwan.|Department of Ophthalmology, Taipei Veterans General Hospital, 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: School of Medicine, National Yang-Ming University, Taipei, Taiwan.
authors.forename: Allen Wen-Hsiang
authors.initials: AW
authors.lastname: Chiu
authors.affiliation: School of Medicine, National Yang-Ming University, Taipei, Taiwan.|Department of Ophthalmology, Taipei Veterans General Hospital, Taipei, Taiwan.
authors.forename: Catherine Jui-Ling
authors.initials: CJ
authors.lastname: Liu
mesh_terms: D017028:Caregivers; D002648:Child; D004812:Epidemiologic Methods; D005260:Female; D006306:Health Surveys; D006801:Humans; D015994:Incidence; D008297:Male; D009216:Myopia / Q000453:epidemiology*; D010290:Parents; D015995:Prevalence; D012107:Research Design; D012307:Risk Factors; D011795:Surveys and Questionnaires; D013624:Taiwan / Q000453:epidemiology; D014505:Urban Population / Q000706:statistics & numerical data
keywords: cohort study; methodology; myopia; population-based study; schoolchildren