Evidence of shared genes in refraction and axial length: The Genes in Myopia (GEM) twin study

Abstract

PURPOSE. Axial length has been shown to explain up to 50% of the total variance in refraction, with axial length and refraction having a major genetic component. However, no study has attempted to determine whether the correlation between axial length and refraction is explained by shared genetic or environmental factors. METHODS. All twins from Victoria aged 18 years or older were invited to participate in the Genes in Myopia (GEM) twin study through the Australian Twin Registry (ATR). Each twin completed a general questionnaire and underwent dilated objective refraction assessment and measurement of axial length. RESULTS. A total of 612 twin pairs (1224 twins) aged from 18 to 86 years were..