Full Disclosure, I work for ColdAvenger Face Masks.
Fogging is a difficult issue and our mask is only one part of the solution. We designed the masks to protect your lungs and keep moisture away from your skin. That being said, they do a great job with preventing fogging. ColdAvenger masks have a hidden nose-wire built into the binding above the ventilator piece. This helps seal humid air from escaping into your eye-wear. The second component of keeping your glasses from fogging is the coating.
Coatings are applied to new eye-wear and eventually rub off as you clean the lenses. This coating needs to be reapplied to prevent fogging. Cat crap is a great brand, as well as UVEX fog wipes. One of the best solutions is just regular dish soap. Just put a small dab on the lens and then rub it off with a non-scratching cloth. This does wonders in preventing the phase change of water vapor on your glasses.
Lastly, try not to touch your lenses as you can rub off the coating. Also, don't move your eye-wear to your forehead. This changes the temperature surrounding the lens and also adds extra moisture from brow sweat.
I hope this helps. We are passionate about our products and outdoor sports in the winter. For more info you can check out our website, http://coldavenger.com. We will try to answer any questions you may have (about our products).
Here is a link to the most popular option for fat-biking. I suggest looking up as you put it on. This mimics your riding position and will make it more comfortable.
ColdAvenger Pro Half Mask