Single day: directly proportional improvements or diminishing returns?

Since we’re all trying to min-max our vision improvement gains, a solid question is how long one should spend outside. This is a bit of a shot in the dark, but would anyone care to have a go at hypothesising which model would be more accurate?


Does more time outside on any given day lead to directly more improvement proportional to the amount of time spent, or do your eyes hit a certain ‘cap’ after getting enough stimulus and need time to recover? Either seem plausible to me at the moment.

The diminishing returns model would be analogous to the gym, where after a certain amount of training no more effort would improve your workout anymore as your body needs time to rest and relax. Whenever I get the occasional flash of blue light in my eyes, I know it’s the vitreous gel harmlessly tugging on my retina as it retreats and shrinks a little bit, and this often happens long after I’ve stopped recieving stimulus in a dark, close-up room! So this leads me to think the diminishing retruns model might be more accurate, but the way eyes and muscles work are totally different and probably should not be properly compared.

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I suspect your single day doesn’t really matter, except in whether you get more or less distance/myopic defocus than hyperopic defocus.

Cumulatively over time is the rub.

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In my experience it’s the diminishing returns model. As far as I know @jakey also says the same and @Varakari’s summer experiment also reinforce it. @jakey’s advice is at least 3 hour distance vision per day.


Time to go binge on Varakari’s thread :slight_smile:

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He has several, this is the one where he tried to get a lot of distance vision:


It’s usually opposite of what everybody is doing so I’m going to test shuting myself in the darkness. r/IE


Very useful to know, just skimmed the thread and looks like this question has been relatively answered. Thanks for the great help as always :slight_smile:

Best of luck :slight_smile:


Happy to see my thread is useful! Maybe I should summarize my experiences so far somewhere for future reference.

I’m only a single person, so please take my results with a grain of salt. That said, they look a lot like diminishing returns.

Spring 2019 and fall 2019, I had very different outdoor times at similar light levels, and yet the improvement rate with the large outdoor times in fall seemed to be slower than what I got with what was often just 1–2 hours in spring.

So whatever the limiting factor here is, it doesn’t seem to be solved by simply going outside more. But not going outside at all does seem to be bad. Probably, the eyes have a maximum rate at which they change shape, which would be reasonable given that lens-induced myopia wasn’t around when they evolved.


I’m going to go out on a limb and say balance is also a factor. You can’t stare at a screen for 14 hours a day, step outside even for three hours, and use the rest of your day for eating and sleeping and expect to change your vision.

Close, middle, far. Frequent breaks, and the habit of looking far off and changing the focal distance, I think, is key.

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