I'de say pressure doesn't affect them at all.
Or atleast won't affect them any differently then wearing a mask -3atm of air is the same as 3atm of water. just as a kilo of feathers is as heavy as a kilo of lead.
What I would be concered about is the water. If in sea, then salinity might iritate you badly after some while, and might even hurt your eyes, but I don't know about that.
Pollution could also be a problem.
Not being able to see very well should be enough to forget about it I think. It's also a metter of safety. You might not be able to see a thin thread that you've got stuck into for example. Or seeing a Jellyfish (not to mention get burned by one in the eyes
If in the pool then I'de say forget about it at all. Chlorine is supposed to kill living cells. I would'nt want that to touch the membrane of my eye (more than the usual exposure once in a while).
My opinion: do you own pipe/fluid goggles for a nose clip.