The trick is positioning and using the wire nose piece effectively. Fit the mask farther down your nose toward the tip (closer to where the "bulb" of your nose starts) rather than the bridge of your nose. Pinch the wire piece tight in that position. Then, place the nose piece/bridge of the glasses right behind/above where the mask sits. While it may seem a bit strange at first, the positioning allows more air to escape while you breathe so the glasses do not fog.