More than 20% of all school aged children in the United States have vision problems, and low-income and minority children are even more likely to have unmet vision care needs. We use a randomized control trial to evaluate the impact of enhanced vision services provided by a local non-profit organization to Title 1 elementary schools in three large central Florida school districts. That organization provides state-of-the-art screening, comprehensive vision exams and free eyeglasses for low-income children. We find that providing additional/enhanced screening alone is generally insufficient to improve student achievement in math and reading, yet in two of the three counties studied providing free vision exams and eyeglasses significantly improved student achievement in math and reading in grade 5 (but for the most part not in grade 4). The magnitude of the impact ranges from 0.07 to 0.16 standard deviations of the distribution of students’ test scores. The impact on English Language Learner (ELL) students is particularly large, increasing math and readings scores by about 0.15 standard deviations (averaged across grades 4 and 5). Most impacts faded out completely by the second year, but the impact on ELL students’ math scores (0.08 standard deviations in year 2) did not fade out. A simple calculation suggests that providing screening and free eyeglasses has benefits that may be two orders of magnitude higher than the costs.