Nie and colleagues conducted a randomized controlled trial to examine the effects of providing free eyeglasses to junior high school students in a poor rural area of Western China.
In this study, screening and vision testing were provided to 1,974 grade seven and eight students from 31 schools located in northern Shaanxi province in China before they were divided into treatment group and controlled group. Then, free eyeglasses were distributed in treatment schools to students found to need one, regardless of whether they had one already. In contrast, students from the control group schools received an eyeglass prescription for their parents only. The eyeglass usage of the treatment group increased from 31% at the baseline to 72%, while that of the control group increased from 28% to 50%.
The study questioned students about their academic aspirations, administered a standardized exam using items drawn from a bank of questions developed by the Trends in International Mathematics and Science Study (TIMSS), and measured the dropout rate to evaluate the intervention. It was found that:
- Among the students without eyeglasses at baseline, the provision of eyeglasses increased their math achievement (E.S. = +0.196), while there was no effect on students who already had eyeglasses at baseline.
- Providing eyeglasses also increased students’ aspiration for attending academic high schools by 9% on average
- In addition, providing eyeglasses also reduced dropout by approximately 2%.
The authors suggested that the positive results were due to students becoming more motivated to learn, more confident in competing with peers, and more willing to invest time and resources into learning when the barrier to learning posed by vision problems was addressed.