Adult-onset myopia: The Genes in Myopia (GEM) twin study

Abstract

PURPOSE: To report the frequency of adult-onset myopia in a large cohort of Caucasian twins that were assessed as part of the Genes in Myopia (GEM) twin study and to quantify the genetic contribution in adult-onset myopia using the classic twin model. METHODS: All twins aged 18 years or older were invited to participate in the GEM twin study through the Australian Twin Registry (ATR). Each twin completed a standard questionnaire and underwent a comprehensive eye assessment, including cycloplegic objective examination. Adult-onset myopia was defined as having the first spectacle/contact lens correction at the age of 18 years or older. Myopia was defined as spherical equivalent worse than or e..