Three single nucleotide polymorphisms (SNPs) [RDH851 (rs2233789), RDH8E5a (rs1644731), and RDH855b (rs3760753)] were selected, based on the linkage disequilibrium pattern of RDH8 from a previous study, and genotyped for 160 Han Chinese nuclear families with highly myopic (-10 diopters or worse) offspring as well as in an independent group with 166 highly myopic cases (-10 diopters or worse) and 211 controls.