Sunglasses or prescription eyeglasses that darken when exposed to the sun are called photochromic, or sometimes photochromatic. Developed by Corning in the late 1960s and popularized by Transitions in the 1990s, photochromic lenses rely on a specific chemical reaction to UV radiation. For more information about PHOTOCHROMATIC EYEWEAR CLICK HERE.
OC Shades is the authorized dealer for PHOTOSUN XDF Lens Photochromatic Lens Sunglasses made my Corning.