Heredity of interocular similarities in components of refraction: a population-based twin study among 66- to 79-year-old female twins.

The higher prevalence of similarities in isometropia of the spherical equivalent and corneal astigmatism between the MZ pairs compared to DZ pairs is consistent with the view that genetic influences on the refractive elements of the eye, tending to isometropia, continue into older age. The interrelation between CR and AL tends to maintain isometropia of SE irrespective of zygosity.