Overexposure to the Sun Can Happen Indoors and Outdoors

Journal of the American Academy of Dermatology Article Offers Information

About the Recent Development in Sun Protection Provided by Window and

Automobile Glass, and Sunglasses

May 01, 2006, 01:00 ET from American Academy of Dermatology

    SCHAUMBURG, Ill., May 1 /PRNewswire/ -- In the car, at work or walking
 to and from a store, you can't escape the sun's ultraviolet (UV) rays.
 However, new research about the transmission of UV light through window and
 automobile glass and through sunglasses, has led to developments that can
 help protect people from the sun.
     "People should realize that even during everyday activities they are
 receiving incidental sun exposure which harms the skin as it accumulates
 and can result in premature aging, wrinkles and even skin cancer," said
 dermatologist Henry W. Lim, M.D., chairman of the department of
 dermatology, Henry Ford Hospital in Detroit, Mich., and co-author of the
 Journal of the American Academy of Dermatology article entitled,
 "Photoprotection by window glass, automobile glass and sunglasses."
 "Dermatologists and manufacturers of glass products and sunglasses are
 continually working to find better ways to decrease the amount of UV
 radiation being filtered through these items to the skin and eyes. These
 advances are helping to reduce the amount of UV exposure that a person
 receives on a daily basis."
     UV radiation from the sun comes in two forms: ultraviolet A (UVA) and
 ultraviolet B (UVB). UVB has long been associated with sunburn while UVA
 has been recognized as a deeper penetrating radiation that contributes to
 premature aging and wrinkle formation. Both of these types of rays have
 been linked to the development of skin cancer. More than 1 million new
 cases of skin cancer are diagnosed each year.
     Window Glass and Photoprotection
     Window glass filters out UVB rays, but UVA rays are still transmitted
 to the skin through the panes. The type of glass and the type of coating on
 the glass can affect the percentage of UV radiation that is transmitted to
 the body. Most residential buildings have one of three types of glass:
 clear, tinted or reflective. Of these three, reflective glass, the kind
 that eliminates the ability to see the interior of a building from the
 outside during the day, minimizes unwanted solar heat gain and reduces UV
 transmission to less than 25 percent. This means nearly one-quarter of the
 UV exposure, exclusively the longer wavelength UVA, is reaching the inside
 though, remarked Dr. Lim.
     "Most Americans spend 80 percent of their day indoors at work or
 school," stated Dr. Lim. "With the new trend in architecture toward more
 and larger windows in buildings, protection from UV exposure when indoors
 has become an important issue for not only the cost-effectiveness of
 cooling a building, but also for the health and safety of the employees who
 work within it."
     Recent developments in window glass include low-emissivity (low-E)
 glass which has a special surface coating between layers of antireflective
 glass. This type of glass reflects up to 70 percent of solar heat and
 reduces UV transmission through the panes to 20 percent.
     To protect the skin from the damaging rays of the sun when working
 indoors, it is important to: arrange workspace so that the body is not in
 direct sunlight; and use blinds or shades on the windows during peak sun
     Automobile Glass and Photoprotection
     In studies of UV exposure in cars, it was shown that the parts of the
 driver's and passenger's bodies closest to the window received the greatest
 UV exposure. Side and rear windows are usually made from non-laminated
 glass, allowing a significant amount of UVA to pass through to the
 passengers in the car. Most windshields are made from laminated glass, the
 type of glass designed to prevent fragments from shattering onto the
 occupants during an accident and which can filter both UVB and a large
 portion of the UVA rays.
     Tinting automobile glass is an option that allows 3.8 times less UVA
 light to be transmitted to the interior of the car as compared to untinted
 window glass. In a 2004 study of UV transmission and color tint, grey
 tinted laminated glass provided the highest UV protection with only 0.9
 percent of UVA light transmitted versus 62.8 percent transmitted through
 non-laminated clear glass. People who are considering tinting their windows
 should take their car to a professional auto detailing shop, in order to
 ensure that the tinting meets the federally mandated 70 percent of minimum
 visible light transmittance through the windshield.
     "Obviously UVA exposure in a car is influenced by non-glass-related
 factors such as position of the individual in the vehicle, direction of
 travel with respect to the sun, and time of day," stated Dr. Lim. "However,
 the more time a person spends in a car, especially at the same time of day
 such as during a regular commute, can greatly affect the amount of UV
 exposure their skin receives."
     To reduce sun exposure while driving, wear protective clothing, such as
 a long-sleeved shirt and pants, especially when the body is in the sun;
 apply sunscreen generously to any exposed skin before driving, especially
 the hands, forearms and face; and wear protective sunglasses to reduce
 glare and protect the eyes from UV exposure.
     Sunglasses and Photoprotection
     UV radiation is potentially hazardous to the structure of the eyes,
 particularly the cornea, lens and retina, which is why the U.S. developed a
 "sunglass standard," with the latest version published in 2001. Sunglasses
 are classified into three categories: cosmetic sunglasses providing minimal
 UV protection; general purpose sunglasses designed to reduce glare in
 bright light or when driving; and special purpose sunglasses for activities
 such as skiing or going to the beach.
     "The ideal sunglasses should substantially reduce UV exposure to the
 cornea and the lens, including any UV coming from lateral directions, and
 should wrap around the eyes, thereby maximizing eye and eyelid protection,"
 said Dr. Lim. "For even better protection, wear a broad-brimmed hat which
 can help reduce the level of UV radiation reaching the eyes and the
 surrounding area."
     In addition, Dr. Lim recommended the following tips when purchasing
 sunglasses to maximize UV protection:
      -- Look for neutral gray and amber brown lenses that give true color
         rendition, particularly to red and green stoplights.
      -- Seek glasses with a large frame and lenses that cover the entire eye
         and wrap around the side of the eye.
      -- Look for the "100% UV Protection" sticker to ensure that the
         sunglasses meet standards for safe levels of UV protection.
     Expensive sunglasses do not necessarily provide better UV protection,
 according to Dr. Lim. Darkly tinted sunglasses can make pupils dilate and
 increase lid opening, thereby resulting in increased UV exposure to the
 lens of the eye.
     In addition to wearing sun protective clothing, including sunglasses,
 you should follow these sun protection tips and Be Sun Smart(SM):
      -- Generously apply sunscreen to all exposed skin using a Sun Protection
         Factor (SPF) of at least 15 that provides broad-spectrum protection
         from both ultraviolet A (UVA) and ultraviolet B (UVB) rays.  Re-apply
         every two hours, even on cloudy days, and after swimming or sweating.
      -- Seek shade when appropriate, remembering that the sun's rays are
         strongest between 10 a.m. and 4 p.m.
      -- Use extra caution near water, snow and sand as they reflect the
         damaging rays of the sun which can increase your chance of sunburn.
      -- Protect children from sun exposure by applying sunscreen.
      -- Get vitamin D safely through a healthy diet that includes vitamin
         supplements.  Don't seek the sun.
      -- Avoid tanning beds.  Ultraviolet radiation from the sun and tanning
         beds causes skin cancer and wrinkling.  If you want to look like
         you've been in the sun, consider using a sunless self-tanning product,
         but continue to use sunscreen with it.
      -- Check your birthday suit on your birthday.  If you notice anything
         changing, growing, or bleeding on your skin, see a dermatologist.
         Skin cancer is very treatable when caught early.
     May 1 is Melanoma Monday and the launch of Melanoma/Skin Cancer
 Detection and Prevention Month(R). For more information about skin cancer,
 please visit http://www.skincarephysicians.com and click on
     The American Academy of Dermatology (Academy), founded in 1938, is the
 largest, most influential, and most representative of all dermatologic
 associations. With a membership of more than 15,000 physicians worldwide,
 the Academy is committed to: advancing the diagnosis and medical, surgical
 and cosmetic treatment of the skin, hair and nails; advocating high
 standards in clinical practice, education, and research in dermatology; and
 supporting and enhancing patient care for a lifetime of healthier skin,
 hair and nails. For more information, contact the Academy at 1-888-462-DERM
 (3376) or http://www.aad.org .

SOURCE American Academy of Dermatology