The Collaborative Longitudinal Evaluation of Ethnicity and Refractive Error (CLEERE) Study is a multi-center, observational investigation of ocular development and refractive error development in schoolchildren. It adds three clinical centers to the Orinda Longitudinal Study of Myopia (OLSM), begun in 1989, specifically to describe normal ocular growth in children ages 6 to 14 years, and to develop the ability to predict juvenile onset myopia before it is clinically evident. In addition to the more than 1,300 predominantly Caucasian children enrolled in the OLSM, three additional clinical sites enroll African-American, Hispanic, and Asian children. The children are examined annually for at least four years. Examinations include visual acuity, refraction by a variety of methods (cycloplegic autorefraction being the primary outcome measure), cover test at distance and near, accommodative response assessment with the autorefractor, response AC/A ratio measurement, videophakometry, peripheral refraction, and A-scan ultrasonography.