A summary of the latest research on myopia (The myopia boom : Nature News & Comment) published in Nature 2015 March 18 correlates increasing rates of myopia – especially in East Asia – with lack of outdoors time. The mechanism may be the effect of bright light on developing eyeballs. Given the cardiovascular benefits of exercise outdoors (notwithstanding the smog problems in many East Asia locales), the Vitamin D boost from sun exposure, and the links between screen time and insomnia (though that’s more of an evening problem), it behooves all of us to get outside every day. If not fully outside, then at least follow the 20-20-20 rule: every 20 minutes look 20 feet away for 20 seconds… with the 20 feet away being bright sunshine (whether real or generated inside with a light-box).