TRANSITION LENSES (a.k.a Photochromic lenses) are eyeglasses lenses that are designed to be clear (or almost entirely clear) indoors, and to automatically darken in outdoor, bright conditions. Effectively, they are normal eyeglasses that transition to sunglasses, to allow for improved visibility in the absence or presence of light. They are also known as light-adaptive lenses. Photochromic lenses are very useful for driving, sports, and outdoor activities. They can even cut down on the harmful glare of electronic devices