Sunlight could stop short-sightedness.

A spreading pandemic of myopia among the world’s urban children may be avoided if children spend at least two to three hours each day outdoors. Australian scientists from The Vision Centre say there is persuasive evidence that increased exposure to daylight can prevent the permanent short-sightedness and eye damage which now afflicts up to 80-90 per cent of children in cities in East Asia such as Singapore and Hong Kong.
Read article at physorg.com