No eyeglass lens material - not even glass - is scratch-proof. But a lens that is treated front and back with a clear, hard coating does become more resistant to scratching. Nowadays, most types of plastic lenses, including high-index, polycarbonate and traditional plastic materials, have built-in scratch-resistant coatings. At GOGETGLASSES.COM all prescription lenses come with scratch-resistant coating at NO EXTRA CHARGE TO YOU.

Another lens treatment that is beneficial but invisible to the naked eye is ultraviolet protection. Just as we use sunscreen to keep the sun's UV rays from harming our skin, UV treatment in eyeglass lenses blocks those same rays from damaging our eyes. Overexposure to ultraviolet light is thought to be a cause of cataracts, retinal damage and other eye problems.

An ultraviolet treatment is simple and quick to apply to most plastic eyeglass lenses, and it does not change the appearance of the lenses at all. The exception is polycarbonate lenses, which don't need anti-UV treatment because it is an inherent property of the material.

To improve both the vision through the lenses and the appearance of the glasses, an antireflective 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.

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, antireflective 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 antireflective 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 antireflective 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. But 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

In contrast to antireflective coatings, which are very clear, mirror coatings (also called flash coatings) are bold statements of color. Just as the name implies, a mirror coating is highly reflective. The mirrored sunglasses associated with state troopers are one example of a flash coating. The technology has advanced, however, so that today's choices include colors of the rainbow as well as silver, gold and copper metallic mirror coatings. Hot pink, blue - almost any color is available.

Mirror coatings are purely cosmetic: the wearer perceives no difference in vision regardless of what color the coating is. Only those looking at the person wearing the glasses can see the color of the mirror coating. Mirror coatings are generally applied over sunglass-dark lenses. Obviously, a highly reflective flash coating prevents others from seeing the eyes of the wearer

Tints are available on plastic lenses and can be had in almost any color of the rainbow. Lighter, fashion tints are used primarily for cosmetic purposes to enhance a wearer's looks. Darker tints allow the wearer to use the lenses as sunglasses.

Typically, fashion tints are applied in light pink, brown or gray, while sunglasses are usually gray or brown. A tint can be solid, when the entire lens is the same color, or gradient, which is a gradual fade from dark to light, usually fading from the top down.

Other colors can be applied to lenses for different purposes:

Yellow, sometimes referred to as a "blue-blocker" because the color keeps blue light from entering the lens, is often the color of choice for target shooters because it decreases haze and makes objects appear sharper, with more contrast.

Green, or its cousin G-15 (the Ray-Ban lens color), is sometimes used as a sunglass, though brown and gray are the most popular sun shades.

Red is a very uncomfortable color to look through, though it does have applications for certain ocular pathologies. However, some people enjoy seeing the world through "rose-colored glasses.