This post may get moved, but not as many people read the product review page, so I'll take my chances. I follow the Iditarod closely after visiting Alaska a few years back when it was kicking off.

Anyway, this year several of the mushers were using Fog Tech to keep their goggles from fogging up on them. It's a liquid that you wipe over your lenses and it forms a film that disperses the condensation that causes fogging. I bought some, put my glasses in the freezer and took them out 3 minutes later, and sure enough, fog. I wiped Fog Tech on them and repeated. No fog. good product. Do a search for it on your browser.