What are photochromic lenses? A photochromic lens is the type of lens that changes its color/tint depending on the amount of light (ultraviolet rays) that are cast upon the lens. When more light is encountered, the lens becomes darker. Conversely, when less light is shined then the lens becomes lighter in color.
How do photochromic sunglasses work?
The secret is in the active material that gets mixed into the lens material. The material is called Silver Halide and it is mixed evenly within each lens. The Silver Halide is the material that makes the lens change its color based on ultraviolet ray exposure. Most photochromic lenses were originally made out of glass mixed with Silver Halide but recently some lenses are now made out of plastic or even polycarbonate materials.