I don’t think that is some universal thing, because people do wear contact lenses or diving eyeglasses or prescription dive masks.

I think those are for people that normally need corrective lenses (e.g. glasses). Not something special for underwater specifically

EDIT: ah wait I see what the OP was saying… Yeah I don’t think water magically fixes vision problems

I wear glasses, and if I swim with goggles, everything is blurry.

However, there are some interesting optical things that happen with the water. Between the reduced distance you can see and the funky stuff that refractive indices can do, I can understand it feeling like your vision is corrected.

I have a pet peeve about universalizing one’s personal experience. If I felt like my vision were corrected underwater, I wouldn’t assume everyone else’s was too.

OP, have you always been using corrective goggles without knowing?

Absolutely not, I got them in a retail shop. I do not see clearly beyond 50 cm without glasses. I could definitely see crisply a jellyfish on the seabed, probably 3 meters below. I watched a dead jellyfish once at my feet on the beach, and I had to crouch to actually see what it is. I see from the comments it’s clearly not working for everyone, so maybe only myopia rather than farsightedness, and maybe to a certain degree only

Also air is not normally a liquid where most people live.

Fluid≠liquid

Air is a fluid; gases & liquids are both fluids

Are we the only two people this works for? I see all the people saying it’s not true, but I have definitely experienced this myself.

It depends on how nearsighted you are. If you have something like -5 you’ll still notice being nearsighted, whereas someone with only -1.5 might suddenly experience seeing perfectly.

It’s because the refractive index of water is different than air. Also, the pressure has an effect on the eye, changing the default focus. Finally you’ll also have a more narrow vision from goggles or from squinting, which itself helps focus ever so slightly.

If you’re in a pool there’s not a whole lot of details to look at to begin with and we’re not terrible good at judging distances under water anyway. So the whole experience is different and difficult to compare to normal vision.

If you do get goggles with lenses you might want to choose a correction that is a few points under your normal glasses because the water gives you one for free.

A factor may be that you don’t see far in water, and details are big (think these black line at the bottom of the pool, not really hard to see)

Attenuation length is shallow water is relatively short, so even with googles and perfect distance vision, you won’t see much behind 10-20m, and may-be 40-80m in deep water (bit there it’s dark).

Mary glasses wearer still have a vision good enough to see decently at 10m especially when they don’t look for ultra small details.

I have astigmatism in both eyes. I can confirm that it doesn’t matter which fluid I’m in, because everything is always blurry without my glasses.