Nickel Silver RXable Frame w/Spring Hinge 6 Base Curve Ground & Polish Optical Glass makes the clearest lenses because it is free of bubbles, seeds, or haziness that can distort vision. It also has Anti-Reflective coating which is a violet-colored coating on the back of a lens that prevents sunlight from coming in from behind and reflecting off the back of the lens into the eyes. This coating is most useful on water or snow. Lens: 61mm
