Ultraviolet Radiation: Risks and Protection
Ultraviolet radiation. What is it, why is it harmful, and how do you protect yourself?
We’ve all heard this term thrown around before, or abbreviated as UV rays, but exactly what is ultraviolet radiation? When casually used in conversation, people typically refer ultraviolet radiation to the harmful electromagnetic rays emitted from the sun. They are not visible to the naked eye, but can result in harmful effects to our eyes and skin. The Ultraviolet Radiation definition can essentially be broken down into three categories:
UVC rays: These could potentially be the most harmful to our skin and eyes but our trusty ozone layer blocks virtually all UVC rays. Another reason why we should care more about not polluting, as it destroys our ozone layer allowing more harmful radiation to reach us. But we’ll save that discussion for a rainy day...but it never rains in San Diego so we’ll probably never write that article. Anyway, back to UV rays!
UVB rays: In low doses, we love UVB rays. It’s what gives us that golden tan when we’re out in the sunshine chasing down that summertime glow. It does this by stimulating the production of melanin (skin pigment). However, in high doses UVB can be harmful and we can all guess why - too much of it leads to sunburn and other nasty stuff like skin discoloration, wrinkles, or worse...skin cancer.
UVA rays. These are the rays that are closer to visible light, and unfortunately, are the ones that can hurt our eyes. They can pass through the cornea and reach the lens and retina inside the eye. Too much exposure to UVA rays has been linked to cataracts, and macular degeneration.
Why is it harmful?
A number of eye problems have been linked to overexposure to UV radiation. For example, UVB rays contribute to the cause of pinguecula and pterygia...basically just weird looking growths on the eye's surface that result in corneal problems and distorted vision.
Intense short-term doses, UVB rays also can cause photokeratitis, commonly known as “snow blindness.” You know that weird semi painful feeling you get when the glare off the snow (or water, or a quick flash of light) hits your eyes and you feel like you can’t see for a minute? That’s photokeratitis. A severe case of this can cause temporary vision loss for up to 24-48 hours.
The risk for snow blindness is greatest at high altitudes, but it can occur anywhere there is snow if you don't protect your eyes with UV-blocking sunglasses.
HEV radiation stands for high-energy visible (HEV) radiation, or blue light. Similar to UV, HEV rays can penetrate deeply into the eye and can cause retinal damage.Scientific studies have shown that HEV rays have also lead to the development of macular degeneration.
Outdoor Risk Factors
Any of us who spend time outdoors are at risk, to some degree, of the harmful effects of UV and HEV rays. The amount of exposure varies obviously from day to day, but here are some good points to keep in mind to protect your eyes on your next adventure:
- Geographical location. UV rays are more harsh in tropical areas close to the equator. You probably could have guessed this since just being in the sun feels noticeably more intense on your skin, and that tan or sunburn can happen in about 15-20 minutes if you don’t block up.
- Altitude. UV rays are stronger at higher altitudes, and the likelihood of the harsh glare off the snow causing a little snow blindness is increased as well.
- Time of day. UV and HEV levels are highest when the sun is directly overhead, usually around 10 a.m. to 3 p.m
- Setting. UV and HEV rays are stronger in wide open spaces, especially around a body of water or snow. In fact, UV exposure can nearly double when it’s reflected off snow. Pretty crazy right? On the other side of the coin, UV exposure is significantly reduced in cities and forests because of the buildings and trees blocking the direct exposure to sunlight.
- Medications. This might seem surprising but certain medications, such as birth control pills, diuretics and tranquilizers, can increase your body's sensitivity to UV and HEV radiation. So the same amount of sunlight you’re used to on a daily basis might prove to be too much if you’re on certain meds. We always recommend meds in small doses anyway...stay natural my friends.
- Cloud cover: Surprisingly enough, cloud cover does NOT affect UV levels because, remember, UV rays are an invisible radiation, not visible light, so it easily penetrates clouds and makes it down to your skin and eyes just the same. We see cloudy days as an increased risk because people tend to not wear sunblock or sunglasses due to the cloud cover, but can still end up with hurt eyes and sunburned skin at the end of the day.
Don’t worry! Protecting yourself from these harmful UV rays is fairly easy if you do it right. We always recommend buying a high quality pair of 100% UV protection sunglasses that block out UV rays and also absorb most HEV rays. This doesn’t have to be an expensive endeavor, but it will be worth the few extra bucks spent on quality shades compared to cheap sunglasses that can actually cause more damage to your eye than not wearing any at all. When shopping for shades, always look for the label that says the UV protection. Best bet is to buy sunglasses from a known brand or retailer, instead of a random accessories shop at the mall.