New perspectives on the prevention of myopia

The high prevalence of myopia and its public health and clinical consequences make prevention of myopia a top priority. Traditional approaches to prevention have been based on reducing accommodative load, and have generally been unsuccessful. Only treatment with atropine eye-drops has produced clinically significant effects, which are however of limited duration and suffer from potential side-effects. In addition, based on animal experimentation, it is now clear that atropine blocks eye growth by mechanisms which do not involve accommodation. More generally, experimentation on animal models of myopia has shown that accommodation is not important for the control of eye growth, whereas exposure to hyperopic (growth-promoting) and myopic (growth-inhibiting) defocus is more important. Recent epidemiological evidence has also questioned the importance of near work, although education is clearly important. This suggests a preventive approach based on deliberately increasing the amount of myopic defocus a child is exposed to may be successful. There is also convincing evidence that children who spend more time outside are less likely to become myopic, which also suggests a quite non-invasive approach to prevention. These new directions need to be pursued.