Heritability of Spherical Equivalent

Purpose To examine the heritability of spherical equivalent (SE) in older women. Design Population-based twin study. Participants Ninety monozygotic (MZ) and 86 dizygotic (DZ) female twin pairs aged 63 to 76 years who were born from 1924 through 1937. Methods Ocular refraction was measured using an autorefractor and controlled by the subjective method. The contributions of genetic and environmental factors to individual differences in SE were estimated by applying an independent pathway model to twin data. Main Outcome Measures Contribution of genetic and environmental effects to the variation in SE. Results Mean SE of the study population was 1.68 (standard deviation, ±1.82) with no differ…