This Cure allows your Eyeglasses lenses to darken routinely when exposed to the Solar's UV rays. The tint then speedily disappears whenever you go indoors. Photochromic lenses can be found in nearly all lens materials and models. 1940s blended Listening to assist Eyeglasses, on Exhibit at Thackray Museum of Drugs.[2] https://www.polette.com/us/opticals.html