An essential part of getting a pair of eyeglasses is deciding on the lenses. Eyeglass lenses can be made from plastic, glass, hard resin, or polycarbonate. Plastic, the most used material for lenses, is impact resistant and lightweight, but it is easily scratched. Glass is scratch resistant, but heavy and breakable. Most everyday-use eyeglass lenses are made of hard resin. Hard resin lenses are lightweight, provide good optical quality, and are resistant to scratches. They can also be upgraded with color tints, UV protectants, or photochromic materials that cause them to darken in bright sunlight. Polycarbonate lenses are designed for high impact resistance, and are ideal for occupational hazards, children, and athletes. They provide the best eye protection.
Here are some of the additional eyeglass lens features that are now available:
Non-Glare Eyeglass Lenses
Reflections and glare can cause a loss of visual acuity and clarity. Glare can also be reflected on the front of the lens, preventing other people from seeing through your lenses, making it harder to make eye contact, and decreasing your cosmetic appearance. Bright office/school lighting also causes glare to be reflected off computer screens or white boards, causing unnecessary eye strain and fatigue. Eyeglass wearers driving at night are exposed to glare from oncoming traffic and street lights, which causes a reduction in visibility.
Non-glare eyeglass lenses allow up to 99 percent of light to reach the eye, improving contrast sensitivity by 20 percent. The foundation of non-glare lenses is a scratch-resistant coating that can lengthen the life of your lenses and reduce the incidence of surface scratches.
How they work: The lenses consist of several layers of metal oxides applied to the front and back lens surfaces. Each layer is designed to block reflected light. External reflections mask your eyes, but with a non-glare lens, reflections are eliminated, leaving your eyes visible so you can make better eye contact with others.
Premium non-glare has a scratch-coat layer that is applied to both sides of the lenses, rather than just to the front. Premium lenses will also have a “hydrophobic” surface layer that prevents water spots from rain, snow, or fog. Then there is the “oleophobic” surface layer that repels skin oils, smudges, and fingerprints. After 20,000 cleanings, premium non-glare has continued durability.
Photochromic Eyeglass Lenses
These lenses change automatically to a sunglass dark tint within seconds when you go outdoors. Constant variations in light intensity throughout the day can leave eyes feeling tired and sore, but photochromic lenses reduce glare, thereby reducing squinting, eye strain, and eye fatigue for wearers.
How they work: Photochromic eyeglass lenses change from clear to dark, depending on the amount of ultraviolet light they are exposed to. It is important to note that since vehicle windshields block UV light, photochromic lenses will not darken while driving. It is recommended that all drivers have a pair of polarized sunwear.
Polarized Eyeglass Lenses
There are three main benefits to having a pair of polarized sunglasses. One is they improve driving safety by eliminating blinding glare from the sun. If you have ever been driving toward a sunset and had a difficult time seeing clearly, you have experienced this kind of blinding glare.
The second benefit is that they protect your eyes from the sun’s harmful rays. Polarized eyeglass lenses block 100% of UV rays, and some brands even block the sun’s high-energy visible (HEV) radiation; also called “blue light.” Extended exposure to the sun’s UV rays has been linked to eye damage, including cataracts, macular degeneration, pterygia, and photokeratitis. New research suggests that HEV rays may increase your long-term risk of macular degeneration. The risk of damage to our eyes and skin from solar UV radiation is cumulative, meaning the danger continues to grow as we spend time in the sun throughout our lifetime. With this in mind, it is especially important for kids to protect their eyes from the sun, as they generally spend more time outdoors.
The third benefit to polarized sunglasses is their usefulness in various sports and other activities. They can enhance your experience and improve your game. Below is a chart to help you choose the best color lens for your sport:
|Activity||Recommended Color(s)||Recommended Materials & Styles|
|Baseball||Gray or Green||Consider background, day or night games. Mirror coatings reduce the intensity of surface reflections and infrared for a cooler eye while standing in the field. Include back surface non-glare and impact resistant material.|
|Cycling||Most Browns, Some Greens, or Copper to enhance contrast||High contrast brown and green to see road hazards, high impact resistant materials for safety. Polarized to reduce scatter and early AM road reflections. Wrap protects from dust and wind.|
|Driving||Gray or Brown||Brown to brighten contrast. Non-Glare for clarity. Polarized for safety to remove blinding reflections.|
|Fishing||Brown, Amber and Gray||Polarized works best to see into water. Gray is darker and brown enhances contract. Low light, overcast or dusk try amber.|
|Golf||Green and Brown||Always non-glare. Newer golf eyewear filters are green or lavender.|
|Motorcycling||Most browns, some gray and green||High speed needs high contrast and high impact resistance. Non-glare improves clarity and safety. Polarized may affect instrument visibility, and care in tunnels is needed. Photochromics are great but not polarized.|
|Skiing||Brown and Amber||High contrast brown and amber are best. High impact resistance and wrap for high speed. Polarized lenses can improve safety because they show ice as black, snow as white and always need non-glare.|
The Cost of Eyeglass Lenses
Having a primary pair of eyewear for everyday use and a pair of polarized sunglasses may not be economical for everyone. Although having a primary pair of eyewear, a pair of polarized sunglasses, a back-up pair, and possibly another pair for personal activities or computer use is ideal, it can be a financial burden. Eyewear should be considered an investment in your vision, however, and many facilities will extend a multiple-pair discount for a couple of months from the time of initial purchase.