Role of Genetic Factors in Lower- and Higher-Order Aberrations – The Genes in Myopia Twin Study

Abstract

Aims: 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. Conclusion: 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.

Micrometric Control of the Optics of the Human Eye: Environment or Genes?

“…The estimation of heritability of ocular SA in the Korean-population study (71%) was above our value (57%), which might reflect population differences, sample differences, and methodological differences. In a previous study, Dirani et al 27 found an estimated value of heritability of ocular SA of only 8%, much lower than our values, which might be the consequence of a smaller sample (46 twin pairs) where correlations did not reach statistical significance.…”

Non-contact measurement of linear external dimensions of the mouse eye

“…This sets a boundary on linear measurement accuracies. Given that for practical purposes of measuring eye dimensions in the mouse, an accepted assumption is that a 6 micron change in axial A-P length corresponds to about 1 diopter of refractive change (Schmucker and Schaeffel, 2004b), so that a resolution of <6 microns should in general be sufficient for most vision sciences laboratory measurements of length, such as those needed in most myopia or optical aberrations experiments, quantitative trait locus experiments (Prashar et al, 2009; Wagner et al, 2008; Williams et al, 1998; Zhou et al, 2001; Zhou and Williams, 1999a), and mutational analyses (Glaser et al, 1994; Hill et al, 1992, 1991; Jablonski et al, 2005; Puk et al, 2006) in mice or other species (Dirani et al, 2009; Yeh et al, 2007). The measured resolution of the laser micrometer was 0.7679 microns.…”