title: The prevalence of anisometropia, amblyopia and strabismus in schoolchildren of Shiraz, Iran.
abstract: OBJECTIVE
  To determine the prevalence of amblyopia, anisometropia, and strabismus in schoolchildren of Shiraz, Iran.
  
  
  METHODS
  A random cluster sampling was used in a cross-sectional study on schoolchildren in Shiraz. Cycloplegic refraction was performed in elementary and middle school children and high school students had non-cylcoplegic refraction. Uncorrected visual acuity (UCVA) and best corrected visual acuity (BCVA) were recorded for each participant. Anisometropia was defined as spherical equivalent (SE) refraction difference 1.00D or more between two eyes. Amblyopia was distinguished as a reduction of BCVA to 20/30 or less in one eye or 2-line interocular optotype acuity differences in the absence of pathological causes. Cover test was performed for investigating of strabismus.
  
  
  RESULTS
  Mean age of 2638 schoolchildren was 12.5 years (response rate = 86.06%). Prevalence of anisometropia was 2.31% (95% confidence interval [CI], 1.45 to 3.16). 2.29% of schoolchildren (95% CI, 1.46 to 3.14) were amblyopic. The prevalence of amblyopia in boys and girls was 2.32% and 2.26%, respectively (p = 0.945). Anisometropic amblyopia was found in 58.1% of the amblyopic subjects. The strabismus prevalence was 2.02% (95% CI, 1.18 to 2.85). The prevalence of exotropia and esotropia was 1.30% and 0.59%, respectively.
  
  
  CONCLUSIONS
  Results of this study showed that the prevalence of anisometropia, amblyopia, and strabismus are in the mid range. The etiology of amblyopia was often refractive, mostly astigmatic, and non-strabismic. Exotropia prevalence increased with age and was the most common strabismus type.
authors.affiliation: Department of Optometry, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: AbbasAli
authors.initials: A
authors.lastname: Yekta
authors.forename: Akbar
authors.initials: A
authors.lastname: Fotouhi
authors.forename: Hassan
authors.initials: H
authors.lastname: Hashemi
authors.forename: Cirous
authors.initials: C
authors.lastname: Dehghani
authors.forename: Hadi
authors.initials: H
authors.lastname: Ostadimoghaddam
authors.forename: Javad
authors.initials: J
authors.lastname: Heravian
authors.forename: Akbar
authors.initials: A
authors.lastname: Derakhshan
authors.forename: Reihaneh
authors.initials: R
authors.lastname: Yekta
authors.forename: Farhad
authors.initials: F
authors.lastname: Rezvan
authors.forename: Mehdi
authors.initials: M
authors.lastname: Behnia
authors.forename: Mehdi
authors.initials: M
authors.lastname: Khabazkhoob
mesh_terms: D000293:Adolescent; D000550:Amblyopia / Q000175:diagnosis / Q000453:epidemiology*; D015858:Anisometropia / Q000175:diagnosis / Q000453:epidemiology*; D002648:Child; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007492:Iran / Q000453:epidemiology; D008297:Male; D015995:Prevalence; D013285:Strabismus / Q000175:diagnosis / Q000453:epidemiology*; D015351:Vision Screening; D014792:Visual Acuity