Polarized lenses in sunglasses work to reduce glare by allowing only vertically polarized light to enter the lens. Outdoor enthusiasts and sports-minded people are the most likely to know about the advantages of polarized sunglasses photochromic lenses and mirrored coatings. These are the three most common methods used to reduce glare and reflect bright light while outdoors. Avid sports enthusiasts are not the only people who can benefit from these types of lenses. The popularity availability and versatility of these lenses are increasing dramatically. In addition to being worn by skiers golfers bikers boaters fishermen and joggers they can be beneficial to drivers and general users.
Polarization Horizontal surfaces such as a paved road reflect most of the glare that interferes with vision. When light waves reflect off a surface they are polarized to equal the angle of that surface. An extremely reflective horizontal surface such as a lake will produce a lot of horizontal polarized light. Polarized lenses in sunglasses work to reduce glare by allowing only vertically polarized light to enter the lens. The lens absorbs all other directions of light.
A chemical film is the most common method of making polarized filters. The film is applied to the lens during the manufacturing process. It is important to note however that the goal of polarization is to reduce glare not to provide ultraviolet protection. Polarization is distinguishable from sunglass tints in that they have coloured coatings on the lenses to filter out various light wavelengths.
Polarized lenses are available for bifocals progressive photochromic and single-vision lenses. Thus whether you spend time on the water ski slopes mountain trails or in your car polarized sunglasses are an excellent add-on to your sunglasses.
Photochromic Lenses Photochromic lenses are ideal for people who do not want to switch between prescription eyeglasses and prescription sunglasses. They provide the convenience of having a pair of sunglasses and transparent glasses in one pair of lenses. These lenses have millions of light absorbing molecules. The molecules are transparent in artificial light which is free of UV rays. When exposed to UV rays from natural sunlight however the molecules undergo a chemical process causing them to absorb light and to darken. These light-sensitive lenses darken automatically after approximately 30 seconds of natural light and lighten after approximately 5 minutes of artificial light. Although photochromic lenses are acceptable for everyday use polarized lenses are a better alternative for high glare sports such as boating or skiing.
One drawback to wearing photochromic lenses however is that the windows and windshield of most modern cars have a factory standard UV blocking coating the lenses will not darken while in the car unless the windows are rolled down.
Mirrored Coatings To reduce glare a mirrored coating works to reflect bright light. It reduces the amount of visible light that reaches the eye but it does not block UV light. The mirrored coating is made by bonding a thin layer of vaporized metal to the surface of the lens. The coatings are available in a variety of fashionable colours.