PRICE (Potentiating Rural Investment in Children's Eyecare) will use a randomized, controlled design across 4 groups of all 138 schools in Yunnan (one of China's poorest provinces) and Guangdong (one of the richest) to optimize the model of "free glasses for all with an optional upgrade." The selection of free spectacles and cost of the "upgrade" options will be varied between groups in order to find the optimal balance between high rates of purchase of upgrade glasses on the one hand and good acceptance and wear of free spectacles among those selecting them on the other.