Strabismus and amblyopia in Iranian schoolchildren

Purpose To determine the prevalence of amblyopia and strabismus among the population of school children mashahd, Iran Methods In a cross‐sectional study with cluster sampling, 2510 school children were selected from schools of district one in Mashhad. Uncorrected visual acuity (UCVA) and best corrected visual acuity (BCVA) were recorded for each participant. 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. Results Of the 2510 selected population, 2150 school children participated (response rate of 85.6%). The prevalence of amblyopia was 1.9% (95% CI: 0.94 ‐ 2.90); 2.1% (95% CI: 0.10 ‐ 3.16) in girls and 1.7% (95% CI: 0.30 ‐ 3.12) in boys (P=0.620). Among myopic, hyperopic and astigmatic students, 3.7%, 27.8% and 6.5% had amblyopia respectively (p<0.001). the causes of amblyopia were 65.9%, 24.4% and 9.8% anisometropia, strabismus and Isoametropic respectively. The prevalence of strabismus was 3.1% (95% CI, 1.3% to 4.3%); 4.2% (95% CI, 3.05 to 5.7%) in girls, and 2.0% (1.3% to 2.9%) in boys(P=0.0011). Strabismus was significantly more prevalent among hyperopic students compared to myopic ones. Conclusion Results of the present study indicate that, the prevalence rate of amblyopia was in the mid range and the prevalence of strabismus was relatively high. Since refractive errors, especially hyperopia, are responsible for some cases of strabismus, a timely diagnosis and treatment can prevent a high percentage of cases with amblyopia and strabismus in children.