Disparity of Central-Peripheral Refraction Inheritance in Twins

The large incidence of myopia during the last decades is becoming a worldwide public health problem. Increasing myopia during childhood has been related to changing lifestyle and linked to larger eye growth, although the mechanism to explain how visual exposures affect ocular development is still unclear. The gene-environment interaction in myopia was investigated in a sample of 100 pairs of young twins with large prevalence of myopia. A classical twin’s study model was performed on objective refraction measured with an open-view peripheral wave-front sensor across a wide range of horizontal retinal eccentricities. In this sample, variance of refractive errors at the area surrounding the line of sight was mainly related to variance in shared-environmental exposures. From there, while moving towards the retinal periphery, the environmental influence over peripheral refractive error variance decreased gradually towards a genetically-driven model. In conclusion, environmental exposures, responsible of the increase in myopia incidence, seems to be affecting mainly the central area of the retinal in young myopes.