Cluster-randomized controlled trial of the effects of free glasses on purchase of children's glasses in China: The PRICE (Potentiating Rural Investment in Children's Eyecare) study

Xiuqin Wang, Nathan Congdon, Yue Ma, Min Hu, Yuan Zhou, Weiqi Liao, Ling Jin, Baixiang Xiao, Xiaoyi Wu, Ming Ni, Hongmei Yi, Yiwen Huang, Beatrice Varga, Hong Zhang, Yongkang Cun, Xianshun Li, Luhua Yang, Chaoguang Liang, Wan Huang, Scott Rozelle, Xiaochen Ma, Xiuqin Wang, Nathan Congdon, Yue Ma, Min Hu, Yuan Zhou, Weiqi Liao, Ling Jin, Baixiang Xiao, Xiaoyi Wu, Ming Ni, Hongmei Yi, Yiwen Huang, Beatrice Varga, Hong Zhang, Yongkang Cun, Xianshun Li, Luhua Yang, Chaoguang Liang, Wan Huang, Scott Rozelle, Xiaochen Ma

Abstract

Background: Offering free glasses can be important to increase children's wear. We sought to assess whether "Upgrade glasses" could avoid reduced glasses sales when offering free glasses to children in China.

Methods: In this cluster-randomized, controlled trial, children with uncorrected visual acuity (VA)< = 6/12 in either eye correctable to >6/12 in both eyes at 138 randomly-selected primary schools in 9 counties in Guangdong and Yunnan provinces, China, were randomized by school to one of four groups: glasses prescription only (Control); Free Glasses; Free Glasses + offer of $15 Upgrade Glasses; Free Glasses + offer of $30 Upgrade Glasses. Spectacle purchase (main outcome) was assessed 6 months after randomization.

Results: Among 10,234 children screened, 882 (8.62%, mean age 10.6 years, 45.5% boys) were eligible and randomized: 257 (29.1%) at 37 schools to Control; 253 (28.7%) at 32 schools to Free Glasses; 187 (21.2%) at 31 schools to Free Glasses + $15 Upgrade; and 185 (21.0%) at 27 schools to Free Glasses +$30 Upgrade. Baseline ownership among these children needing glasses was 11.8% (104/882), and 867 (98.3%) children completed follow-up. Glasses purchase was significantly less likely when free glasses were given: Control: 59/250 = 23.6%; Free glasses: 32/252 = 12.7%, P = 0.010. Offering Upgrade Glasses eliminated this difference: Free + $15 Upgrade: 39/183 = 21.3%, multiple regression relative risk (RR) 0.90 (0.56-1.43), P = 0.65; Free + $30 Upgrade: 38/182 = 20.9%, RR 0.91 (0.59, 1.42), P = 0.69.

Conclusions: Upgrade glasses can prevent reductions in glasses purchase when free spectacles are provided, providing important program income.

Trial registration: ClinicalTrials.gov Identifier: NCT02231606. Registered on 31 August 2014.

Conflict of interest statement

Competing Interests: The free glasses used in this study were supplied by OneSight, Luxottica-China, and Essilor-China, producers of frames and lenses in China. The authors have no other financial relationships with any organisations that might have an interest in the submitted work in the previous three years; and no other relationships or activities that could appear to have influenced the submitted work.

Figures

Fig 1. Enrolment and progression of children…
Fig 1. Enrolment and progression of children through the study.

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