Role of genetic factors in the etiology of juvenile-onset myopia based on a longitudinal study of refractive error

In an attempt to determine the role of genetic factors in the development o f myopia, we examined the relationship of infantile refractive error and pa rental history to juvenile-onset myopia and analyzed 43 pedigrees affected by juvenile-onset myopia. Refraction data collected at regular intervals fr om a sample of juvenile subjects participating in a 24-year longitudinal st udy of refractive error were used, Results showed that children with two my opic parents were 6.42 times as likely to become myopic as children with on e or no myopic parents, Furthermore, children who had refractions in the lo wer half of the distribution at 6 to 12 months of age were 4.33 times as li kely to develop myopia as children who had refractions in the upper half of the distribution at 6 to 12 months of age. The pedigree analysis indicated that 63% of individuals considered at risk for developing juvenile-onset m yopia actually became myopic, with an equal number of affected males and fe males. These results suggest that juvenile-onset myopia of moderate amounts may be inherited as a complex trait involving both genetic and environment al factors.