Photochromic lenses automatically change the darkness of the lens according to light conditions, making them the perfect lens dusk till dawn. The photochromic molecules responsible for changing lens tint are activated by the sun's ultraviolet radiation and also light, allowing them to handle a wide range of environments, even on cloudy days. The darkness of the lens will adjust within a designated range according to the level of light exposure, making every shade possible – from light to dark and everything in between – and it only takes a few seconds for lens to adjust. All lenses that adapt to light use...