The impact of eyeglasses on the academic performance of primary school students: Evidence from a randomized trial in rural china

About 10% of primary school students in developing countries have poor vision, yet in virtually all of these countries very few children wear glasses. There has been almost no research on the impact of poor vision on school performance in developing countries, and simple OLS estimates are likely to be biased because students who study more often are likely to develop poor vision faster. This paper presents results from a randomized trial in Western China that began in the summer of 2004. The trial involves over 19,000 students in 165 schools in two counties of Gansu province. The schools were randomly divided (at the township level) into 103 schools that received eyeglasses (for students in grades 4-6) and 62 schools that served as controls. The results indicate that, after one year, making eyeglasses available increased average test scores by 0.11 to 0.15 standard deviations (of the distribution of the test scores). For those students who accepted the glasses, average test scores increased by 0.15 to 0.22 standard deviations.