Consist of several layers of metal oxides applied to the front and back lens surface. Because of the layering effect, AR coatings sometimes have a hint of green or purple color, depending on the individual manufacturers process. Each layer is calculated to block reflected light resulting in a reduction in glare, annoying reflections and halos around light sources. AR coatings are most useful on water and snow.
Mirror or Flash
Highly reflective and greatly reduces the amount of light that reaches your eyes. Generally applied over a dark sunglasses lens, but can be applied over any base color. Mirror coated lenses absorb anywhere from 10% to 60% more light than uncoated lenses. These are good for higher altitudes, sand, water and snow. Although the most common are the silver, gold and copper metallic coatings, you will find many colors available nowadays.
No lens material is scratch-proof, although a lens that is treated front and back with a clear, hard coating does become more resistant to scratches. Most types of plastic lenses have built-in scratch-resistant coatings.