There used to be a company named Hildago's (possibly out of business now) that you could custom order prescription lenses and pick from several different frame styles. My favorite frames were from Randolf Engineering. They were tough, took a lot of abuse and could be custom configured from ear piece style, nose bridge style, frame width, etc. I never had any problems with helments providing the eye port was big enough. A quick internet search found this: http://www.webbikeworld.com/r4/randolph-engineering-aviator/
