title: Role of genetic factors in lower- and higher-order aberrations--the genes in myopia twin study.
abstract: OBJECTIVE
  We intended to investigate the relative genetic contribution in wavefront aberrations using a sub-group of twins recruited in the Genes in Myopia twin study, and subsequently provide direction for future studies into the aetiology of mono-chromatic aberrations. To our knowledge, the Genes in Myopia twin study is the first study to explore the role of genetic factors in both lower- and higher-order aberrations in a Caucasian population.
  
  
  METHODS
  Each individual completed a general questionnaire and underwent a comprehensive eye examination. Higher-order wavefront aberrations were calculated with Zernike coefficients up to the fourth order.
  
  
  RESULTS
  A total of 46 twin pairs with a mean age of 65.3 years were included in the analysis. Monozygotic intra-pair correlations were significantly higher compared to those in dizygotic twin pairs for defocus aberrations (p < 0.05). A trend for a genetic component was identified for higher-order aberrations.
  
  
  CONCLUSIONS
  Genetic studies into refraction typically explore the genetic effects of lower-order aberrations such as myopia and hypermetropia; however, there is little to no research into the genetic basis of higher-order aberrations. The Genes in Myopia twin study indicates a potential genetic role for higher-order aberrations and provides useful insights into the aetiology of refractive error.
authors.affiliation: Centre for Eye Research Australia, University of Melbourne, Melbourne, Vic, Australia. m.dirani@pgrad.unimelb.edu.au
authors.forename: M
authors.initials: M
authors.lastname: Dirani
authors.forename: M
authors.initials: M
authors.lastname: Chamberlain
authors.forename: T A
authors.initials: TA
authors.lastname: Couper
authors.forename: R H
authors.initials: RH
authors.lastname: Guymer
authors.forename: P N
authors.initials: PN
authors.lastname: Baird