Originally Posted by Jim from Boston

IME, and from reading numerous posts on the subject, there are three basic methods for preventing fogging, caused by exhaled moist air onto the cold surface of the eyeglasses and goggles:

1. Provide ventilation for the exhaled air, as described in my post; an advantage to the exhaled air is that it keeps the face warm.
2. Prevent the exhaled air from reaching the goggles:
   
   
   I have tried typical, and expensive, double-paned ski goggles, and it seems difficult to keep that exhaled air from entering the seal, especially when forcefully exhaling as when riding uphill. If moisture does get into the tightly sealeld goggles, it can’t get out.
   
   It seems a tight headband would also be uncomfortable. An added benefit to safety glasses is I can mount my Take-a-Look mirror on the rigid earpieces.
3. Antifogging agents, like Cat Crap, soap, spit etc.: I find that when exhaling forcefully, and colder temperatures, say under 20° F, those agents can be overcome. That’s why I suggest

I’m not trying to be contrarian about any methods used, but I am zealous because fogging is a difficult and dangerous challenge to winter riding, and would keep me off the bike for about 3 to 4 months during the year. Every year there are many threads on about the problem.

FYA, I was most impressed by this system by @TuckamoreDew of Edmonton, AB: