Purchase this article with an account.
M. Dirani, M. Chamberlain, R. H. Guymer, P. N. Baird; Heritability for Known Risk Factors in Myopia - The Genes in Myopia (GEM) Twin Study. Invest. Ophthalmol. Vis. Sci. 2007;48(13):3236.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Education has previously been cited as a risk factor in myopia. The GEM twin study sought to assess the genetic contribution of education using a classical twin study.
All twins from Victoria aged 18 years or older were invited to participate in the GEM twin study through the Australian Twin Registry. Each subject underwent a general questionnaire comprehensive eye examination and 18ml of blood was extracted from each participant. Categorical educational attainment data was used with education categories 0 to 7; 0 - no education, 1 - primary education incomplete, 2 - completed primary education, 3 - secondary education incomplete, 4 - completed secondary education, 5 - attending or completed trade school, 6 - attending tertiary education, 7 - completion of tertiary studies.
A total of 612 twin pairs (345 monozygotic and 267 dizygotic twin pairs) with a mean age of 52.36 years (range 18- 86 years) were recruited and examined. A total of 463(39.10%) twins had at least category 6 education and 721(60.9%) were between education categories 3 to 5. There was no significant difference in educational attainment between monozygotic and dizygotic twins (p>0.05). Increased education attainment was significantly associated with spherical equivalent (r = -0.21, p<0.01). There was a significantly higher intra-pair correlation for educational attainment in MZ (r = 0.79) compared to DZ twin pairs (r = 0.50) (p = 0.001). The ACE model was sued to explain the variance in education attainment, with additive genetic effects explaining the majority of the variance in educational attainment (69%) and common and unique environmental factors accounting for 20% and 11% of the variance, respectively.
A greater myopic refraction was associated with higher educational attainment in twins. However, genetic factors explained the majority of the variance in educational attainment and therefore this known myopic risk factor cannot be considered solely to have an environmental component. The genetic component identified in educational attainment suggests a role for gene-environment interactions in myopia.
This PDF is available to Subscribers Only