Seeing is Learning: Vision Care for Middle School Students in China's Rural Areas

Last registered on December 20, 2023


Trial Information

General Information

Seeing is Learning: Vision Care for Middle School Students in China's Rural Areas
Initial registration date
December 13, 2023

Initial registration date is when the trial was registered.

It corresponds to when the registration was submitted to the Registry to be reviewed for publication.

First published
December 20, 2023, 12:55 PM EST

First published corresponds to when the trial was first made public on the Registry after being reviewed.



Primary Investigator

Shaanxi Normal University

Other Primary Investigator(s)

Additional Trial Information

Start date
End date
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
The randomized controlled trial (RCT) was conducted from 2013 to 2014 in rural middle schools located in Shaanxi Province, China. Out of a total of 32 schools, one class each from grade seven and eight were randomly selected. All students within the sampled classes underwent an eye examination, and those identified as myopic were further refracted. The refractionists were from a nonprofitorganization called OneSight, a foundation that aims to provide access to quality vision care and eyewear in underserved communities worldwide. The refractionists
were all participating in a volunteer project that was working in the three sample counties. Among the 32 schools, 16 were randomly chosen as treatment schools where free eyeglasses were manufactured and provided to all myopic students. The baseline survey took place in September 2013, while the endline survey was conducted in May 2014. This study was led by a team consisting of scholars from Shaanxi Normal University and Stanford University under the team of REAP. The project was designed to investigate the impact of addressing students' vision problems on their academic performance, thereby yielding implications for policy regarding student vision issues.

Registration Citation

Nie, Jingchun. 2023. "Seeing is Learning: Vision Care for Middle School Students in China's Rural Areas." AEA RCT Registry. December 20.
Experimental Details


All students were screened for myopia by a team of optometrists employed for the study. These optometrists were all trained by trainers from the Zhongshan Ophthalmic Center, Sun Yat-sen University (among the top ophthalmic centers in China), to ensure standardization and quality. Visual acuity (VA) was tested separately for each eye using tumbling E charts.
Following vision screening, students who failed were taken by bus to a clinic located in the central locations to undergo further vision testing.
After refraction, eyeglasses were manufactured for all students (though the eyeglasses would not be given to the control students until after the endline—and this information was not made availableto anyone) using high-quality equipment that was brought from the United States.
Following the randomization, free eyeglasses were distributed in treatment schools to the students found to require eyeglasses, regardless of whether they already had eyeglasses. Refractionists visited the schools and dispensed the eyeglasses, adjusting them to make sure they fitwell, and answered any questions students had about wearing and caring for their eyeglasses.
Students in control group schools were only provided with an eyeglass prescription and asked to take the prescription to their parents. It was not until after the endline survey was complete that the students in this group received free eyeglasses, and students and teachers in control group schools were unaware that they would be receiving free eyeglasses.
Intervention Start Date
Intervention End Date

Primary Outcomes

Primary Outcomes (end points)
Students' Academic Performance: standardized math scores
Primary Outcomes (explanation)
each student was given a standardized math exam. The questions used in the math exam were drawn from a bank of questions developed by the Trends in International Mathematics and Science Study (TIMSS) testing service. The exam was timed carefully and proctored closely by two
enumerators at each school.

Secondary Outcomes

Secondary Outcomes (end points)
Student's mental health, visual acuity, usage of eyeglasses, aspiration to high school
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
The 32 schools were randomly assigned to either the treatment group or the control group, resulting in 16 schools in each arm. Following the baseline survey, all students from both groups underwent an eye examination. In the treatment group, students identified as myopic were provided with free eyeglasses. Conversely, in the control group schools, students only received a letter containing an eyeglass prescription for their parents. It was not until after completion of the endline survey that students in this group received free eyeglasses; furthermore, neither students nor teachers in control group schools were aware of this provision.
Experimental Design Details
Randomization Method
The randomization process was conducted using Stata
Randomization Unit
schools. To improve power, we conducted the randomization within pairs of schools matched by county and by the number of students found to require eyeglasses in the schools.
Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters
32 schools
Sample size: planned number of observations
2000 middle school students
Sample size (or number of clusters) by treatment arms
16 schools, 1000 middle school students
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
This experiment was designed to detect a minimum effect size of 0.25 standard deviation in math scores, with a statistical power of 80% and a significance level set at 5%

Institutional Review Boards (IRBs)

IRB Name
Panel on Medical Human Subjects,Standford University
IRB Approval Date
IRB Approval Number


Post Trial Information

Study Withdrawal

There is information in this trial unavailable to the public. Use the button below to request access.

Request Information


Is the intervention completed?
Intervention Completion Date
May 01, 2014, 12:00 +00:00
Data Collection Complete
Data Collection Completion Date
May 30, 2014, 12:00 +00:00
Final Sample Size: Number of Clusters (Unit of Randomization)
31 schools
Was attrition correlated with treatment status?
Final Sample Size: Total Number of Observations
1910 students
Final Sample Size (or Number of Clusters) by Treatment Arms
Data Publication

Data Publication

Is public data available?

There is information in this trial unavailable to the public. Use the button below to request access.

Request Information

Program Files

Program Files
Reports, Papers & Other Materials

Relevant Paper(s)

We present the results of a randomized trial testing the impact of providing free eyeglasses on academic outcomes of junior high school students in a poor rural area of western China. We find that providing free prescription eyeglasses approximately halves dropout rates over a school year among students who did not own eyeglasses at baseline. Effects on dropout are mirrored by improvements in student performance on standardized exams in math and aspirations for further schooling.

Reports & Other Materials