Beauty And The Bath

Guide For Choosing Lens Materials And Coatings For Your Sunglasses And Eyewear

This a not too technical guide for choosing lens materials and coatings for your sunglasses and eyewear.

Sunglass Lenses
If vision quality is the priority then choose glass lenses.
Choose a plastic lens if safety or impact-resistance is required.

Tempered Glass
Quality glass lenses offer the best viewing quality and the most scratch-resistant. They will be heavier, cost more money and are more prone to shatter when hit.

Organic Plastic
(CR-39) CR-39 organic plastic is thinner and weighs half as much as glass. It exceeds the FDA requirements for impact-resistance.

Polycarbonate Plastic
A remarkable strong plastic, it weighs the least and is the most impact-resistant making it a perfect choice for rugged sunglasses. They also offer built-in ultraviolet. These are a good choice for kids sunglasses, sports & outdoor activities, and safety glasses .


Polarized Sunglasses

For years, polarized sunglasses have been used by boaters and fisherman to reduce glare from the water that they spend so much time on. In the past few years, however, the benefits of polarized sunglasses have been realized by a variety of other outdoor sports enthusiasts as well as by drivers and general use wearers as well. Thus, the popularity of polarized sunglasses has increased dramatically, as has availability.

The activities that utilize the benefits of polarized sunglasses the most include, other than water sports, skiing, golfing, biking, and jogging. For these activities they offer a clearer view and eliminate glare.

How Do Polarized Lenses Work?
Light reflected from surfaces like a flat road or smooth water is generally horizontally polarized. This horizontally polarized light is blocked by the vertically oriented polarizers in the lenses. The result: a reduction in annoying and sometimes dangerous glare.

The bottom line is that whether you spend your time boating or waterskiing, in-line skating or mountain biking, driving at night or jogging at noon, polarized sunglasses are an excellent choice for sunwear.

Guide for choosing lens materials and coatings for your sunglasses and eyewear
Photocromic Sunglasses

What are photochromic lenses? A photochromic lens is the type of lens that changes its color/tint depending on the amount of light (ultraviolet rays) that are cast upon the lens. When more light is encountered, the lens becomes darker. Conversely, when less light is shined then the lens becomes lighter in color.

How Do Photochromic Sunglasses Work?
The secret is in the active material that gets mixed into the lens material. The material is called Silver Halide and it is mixed evenly within each lens. The Silver Halide is the material that makes the lens change its color based on ultraviolet ray exposure. Most photochromic lenses were originally made out of glass mixed with Silver Halide but recently some lenses are now made out of plastic or even polycarbonate materials.

Guide for choosing lens materials and coatings for your sunglasses and eyewear

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.

Guide for choosing lens materials and coatings for your sunglasses and eyewear
Mirror or Flash

United ShadesHighly 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.

Guide for choosing lens materials and coatings for your sunglasses and eyewear

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.


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