Wearing a hat with a dark brim is another method of cutting glare to your eyes. Black absorbs light, while white reflects it. This is why athletes put black under their eyes when playing sports. We would look even more ridiculous than wearing sunglasses at night, if we blacked our eyes. Wearing a hat or visor (who wears visors any more?) can help prevent more light from reaching your eyes.
A third way to diffuse light and prevent glare is to wear a dark shirt. White or lighter colored shirts reflect light, and hence can create a glare that can cause eye strain. I'm not saying to wear a black shirt all the time, but wearing a gray or even a tan shirt can make a big difference. It is amazing how much of a difference this simple clothing choice can make.
Protect yourself from migraines triggered by light. There are lots of other ways to protect yourself from light overload. What are your favorites?