شيوع آمبليوپي فانكشنال در مدارس راهنمايي

Functional Amblyopia in Prevalance in Mashhad Education

Introduction: amblyopia is defined as the loss of visual acuity in one or both eyes, without any obvious organic cause. The aim of this study is to compare the prevalance of amblyopia between the students who had been examined before school age and students who did not examine (control group). Methods: in total 1211 boys and girls students in middle school (573 students in grade I and 638 students in grade 3) were randomly examined in different area (North, South, East and West) of region 5 of Mashhad education. The examination included visual acuity, refractive error, and eye deviation. Visual acuity was measured using a Snellen E chart for use at 6m. A Hine Retinoscope performed cycloplegic refraction, with distance subjective refraction by oculus trial lenses. Results: the students age range was from 11 to 17 years with mean of 12.8 years old. The prevalance of amblyopia was 1.92% in grade I students (who examined before school age) and 1.41% in grade 3 students of middle school (control group who did not examine before school age). The chi-square statistic was used to compare the prevalance of amblyopia between two groups of students in grade I and 3. It was not statistically significant (x2= 0.034, p= 0.54). The chi square statistic was also used to test relationship among amblyopia, type of refractive errors and previous family history. The relationships were found to be highly statistically significant (x2= 100.3, p= 0.00, x2-178.2, p-O.OO). Conclusion: preschool age is critical period of development for visual system. However, the prevalance of amblyopia between two groups of students in grade I and 3 of middle school was nearly the same. This indicates that the preschool vision screening for amblyopia was not effective and useful in region 5 of Mashhad education.