Interchangeable lenses sounds like it could be a good idea for some folks, but I can`t even manage to keep track of the whole stinkin frame. If I were trying to maintain the frames plus a set of various small pieces I would be running around with 3D glassed in no time- each side a different color because I couldn`t find two to match! I think I`m much better off sticking with $15 shades and the above mentioned Hardware store nightwear.