Plastic lenses bathed in specialty lens tints can take on any color shade and density. The lens actually absorbs the tint color into the lens material. Tint density is defined as a percentage, where 0% is completely clear, and 100% permits no light to pass through.
A 10% to 20% tint is used for a "fashion" tint, and a 50% to 80% tint is used for outdoor protection from the sun. You may choose your own lens color and customize your sunglass lenses to your specific needs and applications. Choose from gray, brown, yellow and amber colors. Make sure you add UV coating to the tint if you plan on wearing them outside a lot, for protection.
Photochromic Glass Lenses:
The Photochromic lens is the type that automatically changes its color, depending on the amount of light (ultraviolet rays) that hits the lens. When more light is encountered, the lens becomes darker. As you come inside, the lens will lighten up.
Transition Plastic Lenses:
The original transition lens was introduced in 1991 and has since become very popular, This lens isn't designed to take the place of sunglasses. They are designed for people who normally like a tint in their lens and prefer the light weight of plastic lenses instead of glass. All transition lenses come with a scratch resistant coating, 100% UVA and 99.8% UVB protection. They are continually becoming available in more lens styles.
Polarized lenses have the benefit of filtering out reflective glare off water, pavement, and snow. This type of lens works great for fishing, driving, or any other glare intensive activity. Polarized lenses are the best to eliminate both glare and UV light.