title: Prevalence of Refractive Errors among High School Students in Western Iran.
abstract: OBJECTIVE
  To determine the prevalence of refractive errors among high school students.
  
  
  METHODS
  In a cross-sectional study, we applied stratified cluster sampling on high school students of Aligoudarz, Western Iran. Examinations included visual acuity, non-cycloplegic refraction by autorefraction and fine tuning with retinoscopy. Myopia and hyperopia were defined as spherical equivalent of -0.5/+0.5 diopter (D) or worse, respectively; astigmatism was defined as cylindrical error >0.5 D and anisometropia as an interocular difference in spherical equivalent exceeding 1 D.
  
  
  RESULTS
  Of 451 selected students, 438 participated in the study (response rate, 97.0%). Data from 434 subjects with mean age of 16±1.3 (range, 14 to 21) years including 212 (48.8%) male subjects was analyzed. The prevalence of myopia, hyperopia and astigmatism was 29.3% [95% confidence interval (CI), 25-33.6%], 21.7% (95%CI, 17.8-25.5%), and 20.7% (95%CI, 16.9-24.6%), respectively. The prevalence of myopia increased significantly with age [odds ratio (OR)=1.30, P=0.003] and was higher among boys (OR=3.10, P<0.001). The prevalence of hyperopia was significantly higher in girls (OR=0.49, P=0.003). The prevalence of astigmatism was 25.9% in boys and 15.8% in girls (OR=2.13, P=0.002). The overall prevalence of high myopia and high hyperopia were 0.5% and 1.2%, respectively. The prevalence of with-the-rule, against-the-rule, and oblique astigmatism was 14.5%, 4.8% and 1.4%, respectively. Overall, 4.6% (95%CI, 2.6-6.6%) of subjects were anisometropic.
  
  
  CONCLUSIONS
  More than half of high school students in Aligoudarz had at least one type of refractive error. Compared to similar studies, the prevalence of refractive errors was high in this age group.
authors.affiliation: Noor Ophthalmology Research Center, Noor Eye Hospital, Tehran, Iran.
authors.forename: Hassan
authors.initials: H
authors.lastname: Hashemi
authors.affiliation: Noor Ophthalmology Research Center, Noor Eye Hospital, Tehran, Iran.
authors.forename: Farhad
authors.initials: F
authors.lastname: Rezvan
authors.affiliation: Noor Ophthalmology Research Center, Noor Eye Hospital, Tehran, Iran.
authors.forename: Asghar
authors.initials: A
authors.lastname: Beiranvand
authors.affiliation: Lorestan University of Medical Sciences, Khoramabad, Iran.
authors.forename: Omid-Ali
authors.initials: OA
authors.lastname: Papi
authors.affiliation: Department of Optometry, Faculty of Rehabilitation, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Hosein
authors.initials: H
authors.lastname: Hoseini Yazdi
authors.affiliation: Refractive Errors Research Center, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran ; Department of Optometry, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: Hadi
authors.initials: H
authors.lastname: Ostadimoghaddam
authors.affiliation: Refractive Errors Research Center, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran ; Department of Optometry, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: Abbas Ali
authors.initials: AA
authors.lastname: Yekta
authors.affiliation: Dezful University of Medical Sciences, Dezful, Iran.
authors.forename: Reza
authors.initials: R
authors.lastname: Norouzirad
authors.affiliation: Department of Epidemiology, Faculty of Health, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Mehdi
authors.initials: M
authors.lastname: Khabazkhoob
keywords: Astigmatism; Cross-Sectional Study; High School Children; Hyperopia; Myopia; Prevalence