Perfect vision underwater with swimming goggles?

I’m 19 and have been wearing glasses since I was 5. I’m am EXTREMELY nearsighted, and can’t even see my own hand clearly when it’s 3 inches in front of my face. Any closer, it gets clearer but I have to go cross-eyed.

Anyways, my question is regarding a strange incident that happened to me a few years ago while I was in a swimming pool.

I don’t swim much, but when I do, I still wear my glasses. I had some swimming goggles – nothing too fancy, just some regular goggles you can find at any sports store – and I decided to put them on without my glasses. I was above water, and I couldn’t see for crap, but once I got underwater I could see PERFECTLY!

I was freaked out. I mean I have had to wear glasses that resemble the base of a glass bottle, and yet when I put on simple swimming goggles and go underwater in a pool, I see perfect 20/20.

So, what is happening? Is it the water? The glasses?

Thx,

-X-