Welcome to a near-perfect pair of glasses.
Transitions lenses are photochromic lenses that are clear until dangerous ultraviolet radiation (UV) is present. Once outdoors, the brighter the sun, the darker Transitions lenses become. They turn as dark as sunglasses by automatically reacting to the intensity of UV radiation. Therefore, the real difference between polarized lens tint and photochromic or colloquially called Transition lenses is that the standard polarized lens tint sunglasses are permanently tinted sunglass color whereas photochromic or Transition lenses appear like regular ophthalmic eyeglasses until exposed to the sun. When they are worn outside, they appear to turn into sunglasses with the attendant benefits stemming from that.
Since Transitions lenses block 100% of the sun's eye-damaging rays and help to reduce painful, discomforting glare, they protect your eyes on cloudy days, sunny days, and everything in between. Transitions lenses are the most convenient way for you to protect your eyes from the light you can see and the light you can’t. All while helping to improve the quality of your vision and the long-term health and well-being of your eyes.
That means healthy sight for just about everyone, anywhere, anytime without the need to carry or buy a second pair of eyeglasses!