Publications

Protecting Vision with Sunglasses Outdoors

AMC Outdoors, March 2004

By Michael Lanza

Ultraviolet, or UV, light has been around for as long as there’s been life on Earth. So what’s the big deal? Plenty, it turns out. There are three types of UV light:

• UVA makes skin tan, age, and wrinkle; causes premature aging of the eye; and increases the risk of skin cancers like melanoma. UVA passes easily through the atmosphere’s protective ozone layer and constitutes the majority of our total UV exposure.
  
  
• UVB helps the body produce vitamin D, but can also cause sunburn, corneal irritation, cataracts, and immune system damage. Melanoma is believed to be associated with severe UVB sunburns before age 20. Ozone absorbs most UVB, but enough penetrates to remain a threat.
  
  
• UVC rays are the most dangerous, but are blocked by the ozone layer and never reach the Earth’s surface.

While the ozone layer absorbs much of the UV light entering it, ozone loss in recent decades — attributed to chlorofluorocarbons (CFCs) entering the atmosphere from human activities — has reduced our protection from UVA and UVB. The ozone hole over Antarctica made headlines in the 1980s, but in recent years ozone losses of 6 to 8 percent have been found above the United States, Canada, Europe, and Asia.

Vulnerability to all types of UV light increases with age, and UV damage is cumulative, meaning prolonged exposure can lead to eye problems later in life. So wear sunglasses instead of squinting; tomorrow’s going to be a brighter day.

—Michael Lanza is author of The Ultimate Guide to Backcountry Travel, from AMC Books.