What causes myopia?

Abstract

Myopia (nearsightedness) is a highly common eye condition that is predominantly caused by an axial elongation of the eye. Myopia can usually be corrected with negative glasses, contact lenses, and/or laser refractive surgery. Unfortunately, however, high myopia (-6 diopters or more) can lead to structural changes in the retina and optic disc, resulting in sight-threat ening complications. Myopia results from an interplay between genetic and environmental risk factors (eg. nearwork, . higher educational level, playing outdoors). In this thesis, we studied 130.000 patients from myopia studies from all over the world. We discovered that one third of the European population is myopic. 1 in 3 persons with high myopia becomes blind or visually impaired over time. Furthermore, we identified 26 genetic factors for myopia and 9 for axial length. These genetic factors play a role in neurotransmission, ion transport, retinoic acid metabolism, extracellular matrix remodeling, and eye development. Additionally, we described the role of education (an environmental risk factor) in the development of myopia, and we provide compelling evidence of a gene-by-environment interaction; persons with a high genetic susceptibility and a high educational level are more likely to develop myopia than persons with only one of these two factors. The studies described in this thesis have provided considerable insight into the complex genetic and environmental factors that give rise to myopia and refractive error, and they have given us new directions for treating and/or preventing this rising health issue.