Sorry Pablito, but it's the fresh water. I played water polo for years indoors (high humidity) and my eyes always got dried out. I've sailed Lake Floras Oregon, about 100 yards from the ocean and my eyes always get dried out. (When I go over the dune to the ocean they are fine.) I think the fresh water leaches the salts out of your eyes, but I'm not positive.
Incidently, I've been wearing H2Optix for years. Here is my current model:
