Increased prevalence of myopia among children of myopic parents, twin studies, segregation analysis, and our own preliminary analyses from the OLSM support a genetic etiologic component for myopia. In phase 3, we use the phenotypic characterization of children in the Orinda Longitudinal Study of Myopia to identify prevalent cases of myopia and their families. These well-defined phenotypic myopes and non-myopic siblings and their parents are being explored, seeking to develop a panel of candidate genes for myopia and to conduct an allele sharing analysis in these families