Safety of eyeglasses wear for visual acuity among middle school students in northwestern rural China: a cluster-randomised controlled trial

Abstract

Objective To assess the effect of free eyeglasses provision on visual acuity among middle school students in northwestern rural China.Methods and analysis Among 31 middle schools randomly selected from 47 middle schools in northwestern rural China, students were randomly allocated by school to one of two interventions: free eyeglasses (intervention group), and eyeglasses prescriptions given only to the parents (control group). The main outcome of this study is uncorrected visual acuity after 9 months, adjusted for baseline visual acuity.Results Among 2095 students from 31 middle schools, 995 (47.5%) failed the visual acuity screening, 515 (51.8%, 15 schools) of which were randomly assigned to the intervention group, with the remaining 480 students (48.2%, 16 schools) assigned to the control group. Among these, a total of 910 students were followed up and analysed. Endline eyeglasses wear in the intervention group was 44%, and 36% in the control group. Endline visual acuity of students in the intervention group was significantly better than students in the control group, adjusting for other variables (0.045 LogMAR units, 95% CI 0.006 to 0.084, equivalent to 0.45 lines, p=0.027), and insignificantly better only for baseline visual acuity (difference of 0.008 LogMAR units, 95% CI −0.018 to 0.034, equivalent to 0.08 lines).Conclusion We found no evidence that receiving free eyeglasses worsened visual acuity among middle school students in northwestern rural China.Trial registration number ISRCTN17141957.