title: Development of a refractive error quality of life scale for Thai adults (the REQ-Thai).
abstract: OBJECTIVE
  To develop a scale for measuring refractive error quality of life (QOL) for Thai adults.
  
  
  METHODS
  The full survey comprised 424 respondents from 5 medical centers in Bangkok and from 3 medical centers in Chiangmai, Songkla and KhonKaen provinces. Participants were emmetropes and persons with refractive correction with visual acuity of 20/30 or better An item reduction process was employed by combining 3 methods-expert opinion, impact method and item-total correlation methods. The classical reliability testing and the validity testing including convergent, discriminative and construct validity was performed.
  
  
  RESULTS
  The developed questionnaire comprised 87 items in 6 dimensions: 1) quality of vision, 2) visual function, 3) social function, 4) psychological function, 5) symptoms and 6) refractive correction problems. It is the 5-level Likert scale type. The Cronbach's Alpha coefficients of its dimensions ranged from 0.756 to 0. 979. All validity testing were shown to be valid. The construct validity was validated by the confirmatory factor analysis. A short version questionnaire comprised 48 items with good reliability and validity was also developed.
  
  
  CONCLUSIONS
  This is the first validated instrument for measuring refractive error quality of life for Thai adults that was developed with strong research methodology and large sample size.
authors.affiliation: Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand. roongthip_s@yahoo.com
authors.forename: Roongthip
authors.initials: R
authors.lastname: Sukhawarn
authors.forename: Nonglak
authors.initials: N
authors.lastname: Wiratchai
authors.forename: Pyatat
authors.initials: P
authors.lastname: Tatsanavivat
authors.forename: Somwung
authors.initials: S
authors.lastname: Pitiyanuwat
authors.forename: Manop
authors.initials: M
authors.lastname: Kanato
authors.forename: Sabong
authors.initials: S
authors.lastname: Srivannaboon
authors.forename: Gordon H
authors.initials: GH
authors.lastname: Guyatt
mesh_terms: D000293:Adolescent; D000328:Adult; D044466:Asian People; D003261:Contact Lenses; D005139:Eyeglasses; D005163:Factor Analysis, Statistical; D005260:Female; D006304:Health Status; D006305:Health Status Indicators; D006801:Humans; D008297:Male; D008875:Middle Aged; D011594:Psychometrics / Q000706:statistics & numerical data*; D011788:Quality of Life; D012030:Refractive Errors / Q000503:physiopathology / Q000523:psychology* / Q000628:therapy; D054140:Refractive Surgical Procedures; D015203:Reproducibility of Results; D017678:Sex Distribution; D011795:Surveys and Questionnaires / Q000592:standards*; D013785:Thailand; D014792:Visual Acuity; D055815:Young Adult