There are more sunglasses styles than there are sunny days. You’ve got your round lenses, square lenses, shields, polarized, mirrored, and transitional. Attempting to shop for them can be mind-boggling. (When was the last time you thought about your “face shape?”) So let’s narrow the field. In a world of gimmicky updates and throwaway accessories, there are only three styles of sunglasses you need to consider.