Although I couldn't do it in salt water, it stung my eyes too much but that might also be due to me learning to swim in pools instead of the sea.
> The kids had to dive underwater and place their heads onto a panel. From there they could see a card displaying either vertical or horizontal lines. Once they had stared at the card, they came back to the surface to report which direction the lines travelled. Each time they dived down, the lines would get thinner, making the task harder. It turned out that the Moken children were able to see twice as well as European children who performed the same experiment at a later date.
PS: I still have better than 20/20 vision. But, I think your eyes age faster than most people suggest as I can't see as well even at just 35 vs 15.
I wonder if this refers to salt or fresh water. Maybe both, if the density delta between the two is trivial.
Gislen was able to test a few Moken adults in the same way. They showed no unusual underwater vision or accommodation – perhaps explaining why the adults in the tribe caught most of their food by spear fishing above the surface. “When we age, our lenses become less flexible, so it makes sense that the adults lose the ability to accommodate underwater,” says Gislen.