Photochromic Day/Night  glasses Lenses are clear when indoors or at night and automatically darken to a sunglasses tint when exposed to UV sunlight.

 Lenses will begin to clear as soon as they are away from UV sunlight, and will be noticeably lighter and mostly clear within a few minutes. 

They absorb UV radiation that can otherwise damage your eyes. They are an excellent solution for people who hate constantly switching between their reading glasses and their shade.