does the goggle fit you fine? I know that when I wear my Dragon Rogue goggles if I don't wear a bandana around my nose/mouth/cheek area there's a spot where the goggle doesn't hug my skin and air can get through. If the air is coming in not from the vents, it's probably because either the goggle doesn't fit you and is letting air in from somewhere. Of course if its air from the vents just tape those like said above but i've never met anyone who had problems with too much air coming in from vents.
EDIT: The contacts you are wearing might be making your eyes dry out faster, my friend wears contacts and he says that's what happens to him and he has to blink like crazy to stop from tearing up