From the outside mirror lenses look opaque, however, the wearer of the glasses is able to see perfectly fine. Mirrored sunglasses come in several different styles and designs, and are often a good choice for those who like to make a statement. Just make sure to never wear them when playing a hand of cards with your friends!
Reflective & Protective
Mirror coatings (also called flash coatings) are highly reflective coatings applied to the front surface of sunglass lenses to reduce the amount of light entering the eye. This makes them especially beneficial for activities in very bright conditions, such as hiking, skiing or snowshoeing at high altitudes.
These coatings can block an additional 10% to 60% of visible light for greater comfort in highly reflective full-sun environments.