When snorkeling, scuba diving, or just swimming with goggles, you don’t need corrective glass, why does water do this and not air? Both are transparent continuous fluids.
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.
I don’t think that is some universal thing at all, 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
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.
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
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.
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.
Water has a different refractive index (how ever it’s called in English) than air, which means it behaves like a magnifying glass somehow
So some visual defects can benefit from that. Also, you don’t read a book under water so harder to compare.
No water doesn’t fix your eyes, maybe you are just lucky to see a bit better due to the magnification effect.
Also, it distort what you see, mess up with distances and does not have any effect in focus, so if you have issues with focusing or see at close distance that will do nothing for you
*refractive index, for anybody curious
Thanks! Corrected.
Also air is not normally a liquid where most people live.
Air is a fluid; gases & liquids are both fluids
Fluid≠liquid
