I noticed my eyesight gets better after many hours outside not looking at any screen. And worsen after many hours in front of a screen. Is there a name for that?
Your eye is a muscle, focusing only at close range keeps the range of motion tight. Just like your back and neck might get stiff sitting all day.
Sunlight means smaller pupil, wider depth of field, just like a camera.
(My speculation) More light gives you brain more information to clean up or upscale a blurry image. This effect even seems to last when you leave sunlight, for awhile. It's like I fine tuned my neurons to prioritize blur reduction, and it takes awhile for them to fall back into normal processing. If this is true, my guess is that I might be trading off contrast or color details for sharpness.
[1] https://www.aoa.org/healthy-eyes/eye-and-vision-conditions/c...
I used to think the same thing when I just tried not wearing glasses for a while. I could swear that it was awful at first but over time my no-glases eyesight improved tremendously. I then did a really simple distance reading test and it was obvious that it didn't improve at all and the effect was imagined.