"helmet visors" what he said, except...  

The best set-up is a dual visor with the outer visor clear and the inner visor tinted. You can wear your sunglasses inside the clear outer visor and put tinted visor in place when needed, for example landing into a rising or setting sun. Some visors/helmets fit very snug, difficult to put sunglasses on, even the straight temples when you're wearing your helmet.

I always wore the clear visor down, eye protection is important to a pilot. Opened the vents on a pool aircraft and got a face full of dust and sand once...