title: Prevalence of Color Vision Deficiency and its Correlation with Amblyopia and Refractive Errors among Primary School Children.
abstract: OBJECTIVE
  To determine the prevalence of color vision deficiency (CVD) and its correlation with amblyopia and refractive errors among primary school children.
  
  
  METHODS
  In this population-based cross-sectional study, 2160 children were selected from 36 primary schools; 60 students were from each school (10 students in each grade), with equal sex distribution. A complete eye examination including refraction using a photorefractometer, determination of visual acuity (VA) and color vision using a Yang vision tester, and evaluation of ocular media opacity using a direct ophthalmoscope was performed. Children who could not answer at least 4 plates of the Ishihara color test were considered as color vision deficient subjects. Amblyopia was determined if pinhole VA was worse than 0.3 LogMAR (equal to 20/40).
  
  
  RESULTS
  The prevalence of CVD was 2.2% (95% CI: 1.5% to 3%) which was higher in male subjects (37 [3.5%] boys vs. 11 [1.0%] girls, P < 0.001). Mean VA was lower among students with CVD as compared to normal color vision children (P = 0.035) and amblyopia was observed in 8.3% (95% CI: 0.2% to 16.4%) of patients with CVD versus 2.1% (95% CI: 1.5% to 2.08%) of children with normal color vision perception (P = 0.005). A statistically significant correlation between lower VA and CVD was observed (P = 0.023).
  
  
  CONCLUSIONS
  Although CVD was correlated with lower VA and amblyopia, there was no relationship between CVD and the type of amblyopia, refractive error, anisometropia or strabismus.
authors.affiliation: Ophthalmic Epidemiology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran ; Department of Ophthalmology, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Zhale
authors.initials: Z
authors.lastname: Rajavi
authors.affiliation: Ophthalmic Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran ; Basir Eye Safety Research Center, Basir Eye Clinic, Tehran, Iran.
authors.forename: Hamideh
authors.initials: H
authors.lastname: Sabbaghi
authors.affiliation: Basir Eye Safety Research Center, Basir Eye Clinic, Tehran, Iran.
authors.forename: Ahmad Shojaei
authors.initials: AS
authors.lastname: Baghini
authors.affiliation: Ophthalmic Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran ; Department of Epidemiology and Biostatistics, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Mehdi
authors.initials: M
authors.lastname: Yaseri
authors.affiliation: Basir Eye Safety Research Center, Basir Eye Clinic, Tehran, Iran.
authors.forename: Koroush
authors.initials: K
authors.lastname: Sheibani
authors.affiliation: School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Ghazal
authors.initials: G
authors.lastname: Norouzi
keywords: Amblyopia; Color Vision Deficiency; Refractive Error; Visual Acuity