To determine the prevalence of color vision deficiency, and its correlation with amblyopia and refractive error among primary school children, Tehran (Iran), from October 2013 to January 2014.

In this population based cross sectional study 2160 children were selected from 36 primary schools, 60 students from each school (10 students in each grade), with equal sex distribution. Complete eye examination including visual acuity and color vision using a Yang vision tester, refractive error using a photorefractometer and ocular media opacity using a direct ophthalmoscope was performed. Color vision deficiency was considered if a child could not answer to at least 8 plates of Ishihara color test. Amblyopia was determined if the pinhole visual acuity was worse than 0.3 LogMAR (equal to 20/40).

The prevalence of color vision deficiency was 2.2% (95% CI: 1.5% to 3%) in our population. Color vision deficiency was higher in males (37 M/11 F, p<0.001). The mean visual acuity was lower among students with color vision deficiency compared to normal children (p=0.035). Amblyopia was observed in 8.3% (CI: 0.2% to 16.4%) of patients with color vision deficiency versus 2.1% (CI: 1.5% to 2.08%) in normal population (p=0.005). A statistically significant correlation between lower visual acuity and color vision deficiency was observed (p=0.023).

Although color vision deficiency was correlated with lower visual acuity and amblyopia, there was not any relationship between color vision deficiency and the type of amblyopia, refractive error, anisometropia and strabismus.