title: Effect of providing free glasses on children's educational outcomes in China: cluster randomized controlled trial.
abstract: OBJECTIVE
  To assess the effect of provision of free glasses on academic performance in rural Chinese children with myopia.
  
  
  METHODS
  Cluster randomized, investigator masked, controlled trial.
  
  
  METHODS
  252 primary schools in two prefectures in western China, 2012-13.
  
  
  METHODS
  3177 of 19,934 children in fourth and fifth grades (mean age 10.5 years) with visual acuity <6/12 in either eye without glasses correctable to >6/12 with glasses. 3052 (96.0%) completed the study.
  
  
  METHODS
  Children were randomized by school (84 schools per arm) to one of three interventions at the beginning of the school year: prescription for glasses only (control group), vouchers for free glasses at a local facility, or free glasses provided in class.
  
  
  METHODS
  Spectacle wear at endline examination and end of year score on a specially designed mathematics test, adjusted for baseline score and expressed in standard deviations.
  
  
  RESULTS
  Among 3177 eligible children, 1036 (32.6%) were randomized to control, 988 (31.1%) to vouchers, and 1153 (36.3%) to free glasses in class. All eligible children would benefit from glasses, but only 15% wore them at baseline. At closeout glasses wear was 41% (observed) and 68% (self reported) in the free glasses group, and 26% (observed) and 37% (self reported) in the controls. Effect on test score was 0.11 SD (95% confidence interval 0.01 to 0.21) when the free glasses group was compared with the control group. The adjusted effect of providing free glasses (0.10, 0.002 to 0.19) was greater than parental education (0.03, -0.04 to 0.09) or family wealth (0.01, -0.06 to 0.08). This difference between groups was significant, but was smaller than the prespecified 0.20 SD difference that the study was powered to detect.
  
  
  CONCLUSIONS
  The provision of free glasses to Chinese children with myopia improves children's performance on mathematics testing to a statistically significant degree, despite imperfect compliance, although the observed difference between groups was smaller than the study was originally designed to detect. Myopia is common and rarely corrected in this setting.Trial Registration Current Controlled Trials ISRCTN03252665.
authors.affiliation: Department of Agriculture and Resource Economics, University of California, Davis, Davis, CA, USA Stanford Center For International Development, Stanford University, Stanford, CA, USA ncongdon1@gmail.com.
authors.forename: Xiaochen
authors.initials: X
authors.lastname: Ma
authors.affiliation: Key Laboratory of Ophthalmology and Division of Preventive Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China ncongdon1@gmail.com.
authors.forename: Zhongqiang
authors.initials: Z
authors.lastname: Zhou
authors.affiliation: Center for Chinese Agricultural Policy, Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China.
authors.forename: Hongmei
authors.initials: H
authors.lastname: Yi
authors.affiliation: School of Agricultural Economics and Rural Development, Renmin University of China, Beijing, China.
authors.forename: Xiaopeng
authors.initials: X
authors.lastname: Pang
authors.affiliation: School of Economic Management, Xibei University, Xi'an, China.
authors.forename: Yaojiang
authors.initials: Y
authors.lastname: Shi
authors.affiliation: Key Laboratory of Ophthalmology and Division of Preventive Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China.
authors.forename: Qianyun
authors.initials: Q
authors.lastname: Chen
authors.affiliation: Key Laboratory of Ophthalmology and Division of Preventive Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China.
authors.forename: Mirjam E
authors.initials: ME
authors.lastname: Meltzer
authors.affiliation: Department of Clinical Epidemiology, Leiden University Medical Center, Leiden, Netherlands Department of Medical Statistics and Bioinformatics, Leiden University Medical Center, Leiden, Netherlands.
authors.forename: Saskia
authors.initials: S
authors.lastname: le Cessie
authors.affiliation: Key Laboratory of Ophthalmology and Division of Preventive Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China.
authors.forename: Mingguang
authors.initials: M
authors.lastname: He
authors.affiliation: Freeman Spogli Institute of International Studies, Stanford University, Stanford, CA, USA.
authors.forename: Scott
authors.initials: S
authors.lastname: Rozelle
authors.affiliation: Key Laboratory of Ophthalmology and Division of Preventive Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China.
authors.forename: Yizhi
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Key Laboratory of Ophthalmology and Division of Preventive Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China ORBIS International, New York, NY, USA ncongdon1@gmail.com.
authors.forename: Nathan
authors.initials: N
authors.lastname: Congdon
mesh_terms: D002648:Child; D002681:China; D016000:Cluster Analysis; D003695:Delivery of Health Care / Q000191:economics*; D004522:Educational Status; D005139:Eyeglasses; D005260:Female; D006297:Health Services Accessibility / Q000191:economics*; D006801:Humans; D008297:Male; D008433:Mathematics; D009216:Myopia / Q000534:rehabilitation*; D012424:Rural Population