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Comment by arrowleaf | Hacker News Reader

Close-up work (crafts, reading, computers) causing myopia 'makes sense', I heard the same thing as a kid in the States.

It makes me wish we would have had more P.E. classes outside, rather than 'giving our eyes a break' by playing kickball indoors under fluorescence.

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the problem with playing indoor is that your "eye break" only goes so far as the walls of the space, still "close objects" in relative terms. In nature, humans use their eyes to gaze landscape, stars... really far things.

My understanding is that 20 feet or so is optical infinity, so whether you're looking at an object 20 feet away or 20 light years away, your eye muscles are just as relaxed (hence the 20-20-20 recommendation: every 20 minutes, stare at an object 20 feet away for 20 seconds)

I don't know about you, but where I spent my childhood, most things indoors were much closer than 20 feet away.

That's a fairly large room, and we typically don't focus on the furthest point while indoors anyway. So with the 20ft requirement, it's a lot easier to fulfill while being outdoors.

Oh yeah definitely - I was purely commenting on the parent comment's "really far" claim, and noting that it's all the same to the eye muscles once you hit 20 feet - you don't have to (no pun intended) set your sights on the stars to relax your eye muscles.

Well, the real problem is that children's eyes aren't getting enough sunlight exposure to trigger dopamine production, which regulates the lengthening of the eyeballs, while cooped up inside. Eye strain is muscle fatigue, unrelated to myopia.

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