[Myopia: causes and prevention].

Myopia is the most common disorder of visual function in many literate populations, affecting 70% of some specific groups. The causes may lie in genetic or environmental factors. This article discusses the arguments put forward to support of the biological and environmental theories of the cause of myopia. It is argued that the biological theory has never been proven empirically and that the evidence clearly points to the role of close-range work in the prevalence of myopia as a massdisease. Primary prevention is difficult in this situation and compensatory strategies (relaxation, eye exercises) are rather ineffective. Prevention strategies are discussed and a research program to evaluate their effectiveness and efficiency is proposed.