While most consumers are first attracted to a pair of sunglasses because of the frame style, discerning sunglass wearers are often just as interested in the performance features of the lenses. Thanks to recent advances in lens technology, today’s sun lenses boast an almost unlimited array of colors, styles, designs, materials and treatments specifically designed to enhance the wearer’s performance in a variety of sports and other activities. Because sun lenses are so rich in features, they present a great opportunity for eye care professionals to discuss a product’s benefits and recommend a combination of features to best suit each patient’s visual performance needs. Although many sun lenses are loaded with technical features, experienced eye care professionals and retailers say a non-technical explanation of sun lens benefits works best when presenting products to patients. Asking questions about the patient’s occupation or favorite recreational activities is a good way to zero in on their sun lens needs. For example, asking if a patient is bothered by glare or reflections is a natural lead-in to talking about polarized, photochromic or anti-reflective lenses. Sports vision experts emphasize dispensers must not only consider the sport, but also the conditions in which it’s typically played, before prescribing a lens. Tints, mirror coatings, polarizing filters and backside AR all have their uses in athletics but must be dispensed correctly.
Snow activity sports have spawned a large selection of performance lens choices. Many share similar concepts. Both sky and snow produce blue light. Short wavelength blue light, often referred to as “visual noise,” scatters and is likely to focus in front of the retina, reducing the precision of distance vision and causing objects to appear blurred.The selective attenuation of blue light increases contrast and adds brightness to what is being viewed. Comfort is achieved in bright sun, flat light and haze. Using browns and ambers most often, the snow enthusiasts become aware of the changing contours and textures of the surface. Reflected glare is also a problem on snow. Polarized lenses may be appropriate for the recreational skier, but as polarized lenses eliminate almost all reflected glare, they might pose a hazard for the professional or more accomplished, participant.These athletes must be able to spot and respond quickly to ice and water patches.These would be all but invisible with polarized lenses. A more effective choice would be a mirror coating. Mirrors limit glare without eliminating it, offering the contrasts needed. Mirrors also add to the overall absorption of the lens. The denser the mirror coat, the more the absorption.
Polarization is an absolute must for water sports. Reflected glare reduces visual acuity and depth perception. The most efficient way to block the horizontal reflected waves of light is with the use of polarization. Contrast is fast becoming a most critical property of sports eyewear and is particularly important for fishing sunglasses and other water sports. Gray lenses provide a neutral-color, general purpose lens for boaters, but fishermen need different colors for different types of fishing. That’s where contrast lenses can help. Contrast lenses create the ability to determine small differences in color, enabling the wearer to spot a fish in grassy, shallow water, for example. Contrast absorptions are developed by determining the color of the object being focused on and matching the color of the lens to the object. The color of that item will become more vivid.
The other option is to use a lens color that matches the background. That color will be enhanced, so the object being located will be more apparent in its difference. Gray lenses enhance dark fish. Amber lenses accentuate sandy bottoms of shallow water. Brown lenses bring out grassy water bottoms.These and other dark sun lenses benefit from a backside AR coating. Reflections off the back surface of a dark lens will cause discomfort and adversely effect acuity. A backside AR coating will eliminate the annoyance.
Many ardent fishermen are faithful to glass lenses. They believe that glass has the best acuity and the lenses don’t fade or scratch. Regularly wiping salt water from spectacles can quickly cause damage to plastic lenses. As fishing is often an all-day activity, photochromic lenses are quite convenient in varying daylight conditions, if the fisherman chooses to purchase only one pair.
Cycling and Skating
The needs of the cyclist or in-line skater are quite similar to that of the skier. Reflections must be reduced, but water or oil on a road surface must be identified.While using a mirror to reduce reflections, another benefit is added: Mirrors will reduce infra-red. Although I-R hasn’t been found to cause eye damage, it does cause warmth. Lenses treated to filter infra-red prevent the wearer from feeling some of the discomfort of heat building up behind the lenses. This is of particular help to the cyclists wearing the wrap construction performance sunwear. The wrapped eyewear provides full coverage and protection against peripheral light. It also prevents dust and debris from entering the eye. The lenses used in the wrap frames often go beyond the use of steep base curves. Manufacturers have designed plano curvatures that are ophthalmically correct and free of distortion.
Rifle sports are yet another that requires very high contrast lenses. As hunting is often done early in the morning or during the limited light situations found in autumn and winter, most useful would be a yellow lens, like the classic Kalichrome. It lights up the viewing area along with providing the contrast. This color is also most successful with skeetshooters. An anti-reflective coating on both sides of the shooter’s lenses will maximize the transmission of light.
Keeping one’ eye on the golf ball is aided by polarization and attenuating some blue light. When blue light is reduced, both the sky and the grass are muted, making the ball more obvious. Polarization will remove the glare from the surroundings. This, of course, will effect the perspective of seeing the water traps. Like the skier, the quality of the athlete should help with the choice of golf sunglasses.
Racquet Sports and Polycarbonate
Racquet sports or any sport that involves possible impact, requires the use of polycarbonate lenses for safety. Inherently ultra-violet absorptive, the material meets the most rigorous requirements for any eyewear used during prolonged exposure to the sun. Plano polycarbonate lenses have long been manufactured in effective absorptions, polarization and with mirror coatings. More recently, the improved production and back coating methods used in surfaced polycarbonate make the lenses easily tintable to sunglass densities.They are available polarized and may be AR and mirror coated.
Matching Color With Function
Here are some tips for selecting the best sun lens color for specific visual needs. When recommending a sun lens color, always take into account hair color and skin tone.
- Brown/Amber: Provides contrast and minimizes eye strain. Best for high-glare sports like skiing and boating. Excellent choice for driving because they lessen the glare of scattered light from dirty windshields, smog and haze. May cause greens to appear greener and neons to fade.
- Green: Provides contrast in low light and reduces eye strain in bright light. A typical multi-use color for everyday wear.
- Gray: This neutral tone provides true perception and low color distortion. Gray is a general purpose color that does not enhance contrast. It works best when true color values are important.
- Vermilion: Provides good color perception in low light. Very good at contrasting objects against blue and green background, making it a popular choice for ski goggles.
- Yellow: Known for providing excellent depth perception and contrast in low light. Used frequently for shooting glasses.
Reprinted Courtesy 20/20 magazine