UV Protection (Sunglasses)
Ultraviolet radiation, or UV, is one of the many types of light emitted from the sun. UV radiation is divided into three categories: UV-A, UV-B and UV-C. UV-A and B are naturally occurring and not completely absorbed by Earth's atmosphere. UV-C, on the other hand, is absorbed by the atmosphere and, on Earth, comes from man-made sources like welding tools. Scientific evidence shows that long-term exposure to UV-A and B can contribute to a host of physical problems like cataracts, retinal disorders, skin growths and skin cancer, and photokeratitis, a sunburn of the eye's surface (also known as 'snow blindness' and 'welder's burn'). In addition, people who have had cataract surgery can be more vulnerable to UV radiation damage. If you have had cataract surgery and an intraocular lens implant, your optometric physician can advise you about additional precautions.
The good news is that advances in sunglass technology make it easier than ever to protect your eyes from potentially damaging UV light. In fact, most sunglasses filter out as much as 99% of UV-A and UV-B radiation.
Your optometric physician can help you pick out the perfect pair of 'shades.' Here are a few features you should look for in your next pair of sunglasses:
- Screen out 75-90% of visible light.
- Are perfectly matched in color and are free of distortion.
- Lenses that block out 99-100% of both UV-A and UV-B radiation.
- Polycarbonate lenses are best for sports as they provide impact protection.
- Lenses that are gray, green or brown (avoid blue or violet, as these wavelengths of light are more damaging to the retina).
When selecting sunglasses, lens color can make a big difference in comfort and performance. Following are descriptions that should be helpful in making a decision.
|Gray or smoke
||Best for general use and driving, and for situations when depth perception is not as important as true color perception.
|Amber or yellow
in flat, hazy light and for high-speed, high-altitude sports like
skiing. Amber lenses filter out blue light that can make focusing
|Vermilion or pink
to absorb light in foggy or gray conditions. Also helps increase
contrast and depth perception, making them a good choice for high-speed
||Offer the true-color perception characteristics of a gray lens, but also helps remove blue light and increases contrast.
||For use during night or extreme low-light conditions.
More Sunglass Buying Tips:
Look for glasses that have a uniform tint throughout the lens.
- Hold the glasses at arm's length and look through them at an object.
- Slowly move the lens – if the edge of the object sways, curves or moves, the lens has optical imperfections.
- Ask your optometric physician to check your current lenses and to suggest sunglasses that are appropriate for your lifestyle.
Contact lenses now are available with a UV blocking feature. These should not be worn in place of sunglasses, however UV-blocking contacts do provide additional protection by blocking much of the UV radiation that can seep in from above and below your sunglasses.