This study evaluates a field experiment in which a non-profit organization (FLVQ) offered enhanced vision services to a randomly selected group of Title 1 elementary schools in three large central Florida school districts during the fall of the 2011-2012 school-year. This is the first study in the U.S. to use a randomized trial to estimate the impact of vision services on student outcomes. In order to rigorously test of the efficacy of FLVQ’s services, we conducted a randomized trial targeting 4th and 5th grade students in Title 1 schools where FLVQ had not had a significant presence over the last two years. The randomization was done at the school level in three school districts (i.e. three counties). Schools were assigned to one of two intervention groups or to a control group. The first intervention group received additional/enhanced vision screening. The second intervention group received additional/enhanced vision screening as well as free onsite eye exams by an optometrist and free eyeglasses as needed. The control group received no vision services from FLVQ. Preliminary results find that providing additional/enhanced screening alone is not enough to improve student outcomes. In two of the three school districts studied, the intervention which included free exams by an optometrist and free eyeglasses as needed significantly improved student achievement as measured by the FCAT. When we focus on these two school districts, we find that, averaging over all students – including those who did not receive eyeglasses – FCAT level scores (which range from 1-5) increased on the order of 0.08 for reading and 0.09 for math in schools where FLVQ provided screenings and follow-up vision services. This evidence is robust to different specifications and the effect is stronger for low-income students and for students with poor vision. This is a large effect and suggests that vision services are more cost-effective than many other potential uses of district and/or state funds. These preliminary results are based on data from the 2012 FCAT. When the test was administered, students who received free eyeglasses had had their glasses for only a few months. Future drafts will include data for the 2013 FCAT to track the effect over time.