i use them both for airsoft and smoked ones as sunglasses on the bike, never had an issue and taken plenty of hit to the lenses, have stress tested an old pair that got very deeply scratched and have no worries about them.
must depend on the weather as i used mine all day at a Milsim couple weeks ago and they didnt fog at all but i was outside most of the day so maybe if your in door they might like Lozart said, either that or he was working hard and i was being a lazy bastard