It is known that the transition lenses will get dark in sunlight and will turn to clear when get indoors. The transition lens is available in a variety of shades ranging from gray to green. Transitions lenses begin to darken the moment they are exposed to UV light. The greater the intensity of UV radiation, the darker the lenses become. The moment UV rays are no longer present, the lenses begin to fade back. In short, Transitions lenses quickly darken when you go outdoors, and fade back fast when you return indoors. Most wearers report the adjustment happens so smoothly that they are unaware of it since the lenses allow you to seamlessly go from low light to bright light and everything in between.