As the sun gets higher in the sky, more people will be spending time outdoors, for leisure or sporting activities. While most people understand the need to apply sunscreen to protect their skin from overexposure to the sun’s harmful rays, it’s also important to protect your eyes from sun damage.
Sunlight is comprised of a spectrum of ultraviolet light that affect humans, including: UVA and UVB. It is UVA that produces the tanning response in skin, and it comprises 95-99% of the sunlight that reaches the surface of the earth. UVB is the spectrum that enables the body to produce Vitamin D, a substance that is vital to cell function and is believed to help prevent certain cancers, like those of the stomach and colon.
In unprotected eyes, sunlight can cause sunburn on the external lids, eye and cornea, like sunburn on the skin. Sunlight can also affect the inside of the eye. Over time, unprotected exposure to sunlight can increase the risk of cataracts. Direct sunlight can cause damage and premature aging to the retina that can lead macular degeneration or loss of sight. Children are especially vulnerable to damage from UV exposure, as they don’t know enough to complain about bright sunlight and glare. Children have larger pupils than adults and as a result, more light is transmitted inside a child’s eyes. Though adults have smaller pupils, UV light transmitted can still cause damage. Effects from UV damage are cumulative, so early and consistent protection through a lifetime can make a difference.
Your “glasses” are no longer made with glass for safety reasons. Most eyewear is made with a high-grade plastic polymer called CR39. Its properties include about half the weight of glass, chemical resistance and “tint-ability.” Its impact resistance is higher than glass, but should not be considered for activities or sports that risk impact.
CR39 is fine for most people playing most sports because of its light weight and superior refractive qualities. For those eyewear lenses to be used in situations where high impact trajectories play a role, such as racquetball or work with nail guns or bullets, polycarbonate should be used. Polycarbonate is the strongest material available, though not indestructible, but offers lower refractive qualities than CR39. The advantage over CR39 lenses is that when it does break, polycarbonate breaks into larger — safer— pieces.
Tints and coatings can make a difference
Tints and coatings to help screen out UV rays can enhance the performance of sporting eyewear. A tint would be a single addition of color to the lens based upon the most frequent use. Different colors offer different absorptive qualities and can affect the way objects appear when worn. Tints can be selected to enhance vision under variable light conditions. For some sports and activities a lighter lens is better. For activities requiring sharp distance vision, such as golf, a light to medium tint is recommended. For sports with added reflected sunlight from snow, water or sand, a neutral gray tint can reduce the light spectrum evenly to keep colors looking natural and undistorted. Tints by themselves do not reduce UV exposure, but a UV blocker can be included in most lenses. UV blockers can function just as well without a tint, when protection but a clear lens is needed. Lenses that are polarized work specifically on reflective light to block glare from lower angle like water, sand or snow.
These lenses react to the amount of ambient UV spectrum to darken and lighten and are most commonly marketed under the Transitions brand. Transitions has several different types of lenses developed for different applications and provide 100% protection from UVA and UVB light. Original Transitions lighten from clear to moderately dark for eyewear worn both indoors and out. If you spend a good portion of your day outdoors, you may want to opt for Transitions XTRActive lenses, which change from a light tint to very dark outdoors. A new type of lens designed for sunwear applications adjust from dark to darker, depending on the amount of sunlight. This type of sunglass lens has several different options designed for specific activities and sports, in both prescription and non-prescription lenses.
Lenses can also be coated with an anti-reflective coating that will provide additional light reduction and protection while adding clarity, and to cut down on reflections & glare from headlights or reflected sunlight.
Sun protection can be achieved with clip-on or flip down lenses, but in adding another reflective surface in the form of the darker lens of the clip, you may be sacrificing clarity.
Frame styles can enhance protection
In addition to enhancing the good looks of your sunwear, the frames may be selected to provide extra protection. Properly fitting frames become essential for sports or activities where looking up or focusing down are key elements. Wrap-around styles can protect the eyes from snow, debris, water and peripheral glare, but need also to be properly ventilated. Active sports create perspiration and body heat, which can create foggy lenses if air is not able to flow inside the glasses.
The frame materials can also be a factor in selecting a protective eyewear for a sport. Some sports need a rigid frame, while others might need a little flexibility. Sometimes the proper large outer frame for a particular sport makes the prescription lens too heavy or impractical. Smaller inserts can be fashioned to correct and protect vision, without losing the extra protection of a larger mask or wraparound style.
As with all your eyewear, it’s essential to spend some time with your trained optician or optometrist to discuss all the activities and lifestyle applications where your glasses can be modified for maximum performance, comfort and protection.