Purpose:The purpose of this study is to assess the magnitude and determinants of refractive error among school children of Lalitpur and Bhaktapur districts in Kathmandu Valley of Nepal.Materials and Methods:A descriptive study was carried out in 2003 in four schools; two in each district. A detailed ocular examination was conducted of all children attending these schools and that included visual acuity testing, slit lamp examination, fundus evaluation, retinoscopy, cycloplegic refraction and subjective refraction. Myopia was defined as more than −0.5 D and hypermetropia was defined as error of more than +1 D.Results:A total of 2000 students of 5-16 years of age were examined. The prevalence of refractive error was 8.60% (95% confidence interval [CI] 7.37-9.83). The prevalence of myopia was 6.85% (95% CI 5.74-7.96). The best-corrected visual acuity was 6/9 or less in the eye of 12.8% children with refractive error.Conclusions:Refractive error is of public health magnitude among school children of 14-16 years of age. School screening program in countries like Nepal for early detection of treatable disease is useful to detect and correct refractive error in older students.