I have a large head for my size (5'9'' always wear a L/XL hat) and these glasses still fit well. They are snug, but this is not surprising since they are for running and cycling. The lenses that come with the gray frames don't darken the world very much, but cut out a ton of glare and are ideal for suburban running environments. I have worn them at all different times of the day except night (not that cool, sorry) and have never wished for darker lenses. Oh yeah and they have really good peripheral vision. They almost never fog up and come with a stylish tweed case. Recommended for those looking for a serious pair of shades that won't interfere with Insect eyes.
"All the time (almost) goggles for your face!"
The Julbo Runs work well in 80% of the light conditions you experience outside, the other 20% being moonless nights (10%) and super-bright sunsets (10%) on the horizon burning your face off. The rest of the time these can stay on your face! A nice yellow color takes the bite off of everything and the antifog works well too. I only fog them when I'm working hard up hill on my bike going slow. They're great for climbing, boating, bike riding, and any other time you want eye protection. The fit is probably medium to medium large. I submitted a pic of me on top of saddle mountain, my dome is medium-sized in most cases.