Impact of Free Glasses and a Teacher Incentive on Children’s Use of Eyeglasses: A Cluster-Randomized Controlled Trial - Hongmei Yi; Haiqing Zhang; Xiaochen Ma; Linxiu Zhang; Xiuqin Wang; Ling Jin; Naidoo, Kovin; Hasan Minto; Haidong Zou; Lina Lu; Scott Rozelle; Nathan Congdon* (American Journal of Ophthalmology, 2015)