Sun safety – describes a range of behaviors that include wearing wide brimmed hats that cover the face and neck; the correct use of sunscreen of at least sun protection factor (SPF) 15 and limiting sun exposure during the hours of peak sun intensity, 10:00 AM to 4:00 PM. One other important “sun safety” issue is wearing sunglasses that filter out ultraviolet B (UVB) and ultraviolet A (UVA) light. Wearing sunglasses is so important in fact that it can be considered to be the “suntan lotion for the eyes.” Let’s look at some of the detrimental aspects of sun exposure to the eyes and important features in sunglasses for eye protection.
Dangers of sun exposure to the eyes
Ultraviolet light from the sun has been linked to the formation of cataracts, macular degeneration, skin cancer on the lids and pterygium, an abnormal growth on the eye’s surface. Cataracts develop when proteins in the lens of the eye clump together, clouding the vision. Even though cataracts appear to different degrees in most individuals as they age, their development appears to be enhanced by exposure to UVB. Macular degeneration is the leading cause of blindness in the center portion of the visual field in the U.S. There is conflicting evidence as to whether exposure to sunlight contributes to the development of macular degeneration, but at least one study has shown that people who stay outside in the summer sun for more than 5 hours a day in their teens through their 30’s are twice as likely to develop macular degeneration later in life. Just as in other areas of the body in which sun exposure increases the risk of skin cancer, melanoma, basal cell and squamous skin cancers can develop on the skin around the eye if not protected. A ptyerygium is a growth that develops on the white portion of the eye that can extend over the the pupil and obscure vision. These appear to develop as a result of prolonged UV exposure also.
Factors that increase your UV exposure, also increasing your likelihood of developing sun-related problems include: spending time on snow, sand or on the water, being outside at higher elevations or closer to the equator, staying outside between the hours of 10 AM and 4 PM and prolonged sun exposure, particularly in the Spring and Summer.
Will sunglasses prevent these problems?
Sunglasses serve two major functions. They decrease the amount of sunlight reaching your eye for comfort and protect your eye and surrounding structures from the devastating damage of ultraviolet light. By wearing sunglasses regularly, you can decrease your risk of sun-related damage significantly.
The following features will help you to select a pair of sunglasses that are both protective and appropriate for your needs.
- Be sure that your sunglasses block 99-100% of UV light. Both plastic and glass lenses can be coated to so that they block essentially 100% of UV rays. This information should be available on the label.
- The color or darkness of the lens has nothing to do with its ability to block UV rays as the UV coating is colorless. Color choice is personal decision. Green and gray lenses produce minimal color distortion and are probably best for all-round use. Brown offers high contrast and depth perception but does distort color. Vermillion lenses are best for defining water from other objects but distort color badly. Many skiers prefer “blue blocking” sunglasses (typically amber in color) which provide the best contrast in snow and haze.
- Polarized lenses are the best for reducing reflected glare such as sunlight that bounces off of snow or water. Polarization, however, does not have any relation to blocking UV radiation. Wrap around sunglasses will help keep light from shining into your eyes from around the frames. During active sports, they provide some added degree of protection.
- Photochromatic glasses will change from light to dark, depending on the amount of UV radiation that they receive. While most of them offer good UV protection, it can take time for them to “adjust” to different light conditions.
- Remember that sunglasses are necessary even on cloudy days. Clouds might provide shade, but they are no barrier for UV light.
- You need sunglasses even if your contact lenses offer UV protection. A high quality lens can only protect the area it covers, and the entire surface of your eye needs protection.
- Children who cannot tolerate sunglasses should wear a wide-brimmed hat, which will provide some UV protection.
- Do not be misguided by higher priced sunglasses which may be oriented to fashion, not UV protection.
- With sunglasses, you can have it both ways. An attractive pair of sunglasses can also provide adequate sun protection. Be a “label reader” and make sure that your lenses offer the protective features mentioned above.
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