Myopia and the outdoors

Not sure I buy into this, but it makes for an interesting hypothesis.

Myopia, along with several others such as allergies and obesity, seems to be caused by modern lifestyles. But exactly what about how we live is causing the problem? It has never been clear. The usual explanation is too much staring at close up objects. Another idea I had not heard though is that we just don't spend enough time outside.

Sadly I doubt an experiment well enough designed to separate correlation from causation will ever be performed.