Originally Posted by Ken Wind
I have excellent vision, and I don't need to wear glasses or contacts, but I still have a few suggestions.
I wear glasses most often during the winter because the cold and wind hurts my eyes. Last winter I used a pair of cycling sunglasses (Rudy Project Kerosene) that did a fairly good job with fog and rain. When I stopped is when they fogged up mostly. I noticed that it helped prevent fogging when I adjusted the nosepieces to put the glasses a little further away from my face though. If you have adjustable nosepieces on your glasses, then you should try adjusting the position of the glasses. I never had a problem with water fogging up the lenses. It just beads on them. Good cycling glasses are a good investment. Many Rudy Project glasses (and some other brands) can be fit with a prescription insert too.
I ordered a pair of RP Ekynox SGV for this winter, but I haven't received them yet. They come with a pair of double layer anti-fog lenses.
If you don't mind the larger ski goggles, then I've heard that eyeglasses can usually be worn underneath them, but that might not help in the rain.
I've also heard that cat crap is amazing.

I was just thinking about "Cat Crap" - when I used to take swim lessons (3 solid years of private lessons, and I still can't swim!) I used to use that stuff on my goggles to keep from fogging up. Works great, and can be found at some sporting goods stores & swimming pools.