You MUST get polarized lenses. My best friend is an optometrist and I used to wear Smiths, Oakleys, etc... I would always get sunburn in my eyes from long days on the water. He diagnosed this in some of the cases and it was due to inferior lenses.
I would suggest a good quality lens from Maui Jim or Costa.
All lenses fog. The easiest thing to do is to spit clean them. Works every time... Just ask ask a diver...