I've been useing the same Ocean & Earth surf cap for 5 years & it's brilliant. The base of the straps have material to cover my ears. I wear normal sunnies under it which I've just slipped a length of plastic speggetti onto the ends round the back of my head. Haven't lost a pair of sunnies for years. See pics under my profile. It may not be cool, but that's me to a tee.
cheers Col