Purchase this article with an account.
J.M. Ip, K.A. Rose, D. Robaei, S.C. Huynh, E. Rochtchina, A. Kifley, J.J. Wang, P. Mitchell, Sydney Myopia Study, Sydney Childhood Eye Study; Evidence For Gene–Environment Interaction On The Development Of Myopia In A Population Of 12 Year Old Children . Invest. Ophthalmol. Vis. Sci. 2006;47(13):5454.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
To examine influence of parental myopic refraction on childhood refractive error and interaction between parental myopia and outdoor activities.
A random sample of 12 year old children were recruited from 22 Sydney high schools (75% response rate, total of 2367 children, preliminary results for 2000 children). Children underwent cycloplegic auto–refraction, visual acuity testing and completed questionnaires about outdoor and nearwork activities. Parental refraction was obtained from prescriptions, or based on questions about spectacle use when prescriptions were not available. Childhood myopia was defined for spherical equivalent (SE) ≤ –0.50D. Mean SE was compared after adjusting for age, gender and ethnicity.
Children with none, one or two myopic parents had myopia prevalence of 7.3%, 15.9% and 47.5% (p(trend) <0.001), and adjusted mean SE of 0.64D, 0.22D and –0.73D, respectively (p<0.05). Myopia also varied by ethnicity; East–Asian children had a more myopic mean SE (–0.45D) than Caucasian children (0.78D, p<0.0001). For children with none or at least one myopic parent, mean SE was more negative in East Asian (0.05D, –1.04D) than Caucasian children (0.93D and 0.70D), p<0.0001. Number of hours spent outdoors was not significantly different, after adjusting for gender and ethnicity (16.6 hours, 16.3 hours and 15.4 hours, in children with none, one or two myopic parents, p(trend)= 0.13). In children with no myopic parents, refraction was not associated with time outdoors (mean SE 0.52D, 0.60D and 0.44D for the highest to lowest tertiles of hours spent outdoors per week, adjusted for ethnicity and nearwork, p(trend)=0.39). However, for children with at least one myopic parent, increasing time outdoors was associated with a lower level of myopia, mean SE (adjusted for ethnicity and nearwork) ranged from –0.05D to –0.50D for the highest to lowest tertile of outdoor hours per week, p(trend)=0.003).
Findings from this study support possible gene–environment interaction in the development of childhood myopia. We documented a similar parental influence on myopia in Caucasian and East–Asian children even though East–Asian children were consistently more myopic at each parental myopia category. For children with at least one myopic parent, increasing time outdoors appeared to reduce the expected parental effect.
This PDF is available to Subscribers Only