Types of Lenses
To improve both the vision through the lenses and the appearance of the glasses, an anti-reflective coating (also called AR coating) is applied. AR coatings are similar to the coatings found on microscopes and camera lenses. They consist of several layers of metal oxides applied to the front and back lens surfaces. Because of the layering effect, AR coatings sometimes have a hint of green or purple color, depending on the individual manufacturer's formula.Glasses without anti-reflective coating make it difficult to see the wearer's eyes. Glasses with anti-reflective coating show much less surface reflection.
Each layer is scientifically calculated to block reflected light. The result is that you'll see a reduction in glare, annoying reflections and halos around lights. This is a great safety benefit when you're driving at night.
Also, anti-reflective coating reduces both internal and external reflections on the lenses themselves, creating a nicer cosmetic appearance. Internal reflections appear as rings that make lenses look thick. External reflections mask your eyes from a clear, complete view when someone is looking at you. So with an anti-reflective coating, eyeglass lenses appear thin or non-existent, and your eyes look more natural.
Anyone on TV or whose photo is taken often benefits tremendously from the coating, but really, all eyeglass wearers would benefit from an anti-reflective coating from a cosmetic point of view. If you have a strong prescription, you can use the AR coating in conjunction with high-index lenses to make your glasses look and feel as thin as possible.
With sunglass lenses, an AR coating is better applied only to the back surface of the lens (the surface nearest the eye). Because sunglass lenses are so dark, the AR coating can wind up looking smeary on the front surface. Coating the back side helps reduce the reflections of light that enter from behind you and bounce off the surface into your eyes. A back-side coated sun lens is much more comfortable than an uncoated sunglass.
You do have to be careful when cleaning AR-coated lenses. Use only the products that your optician recommends.