Mirror coatings go on the outside of the lens and the color is only visible from the outside. The color you see from the inside is either grey or brown. Mirror coatings help to deflect glare, especially in situations on the water or on the snow. With a full mirror coating, other people cannot see your eyes. WIth a flash mirror coating, your eyes are slightly visible. Mirror coatings do not replace tint colors, so a tint color would need to be added in order to utilize as sunglasses. Mirror coating does not include lens tint: tint must be added separately.