Ultraviolet light is a type of radiation similar to visible light with a shorter wavelength. There are three types of ultraviolet light that affect us, UVA, UVB and UVC. All three are produced by the sun, but only UVA and UVB reach the earth’s surface. UVA causes aging changes and cancer, UVB is responsible for sunburn and cancer and UVC is absorbed by the ozone layer, so it doesn’t pose a threat.
UV light can be beneficial also. UVA is used in medical treatments for psoriasis, vitiligo and keratoconus. UVB helps our bodies make Vitamin D. UVC can kill bacteria and viruses, so it is used to sterilize medical devices.
Exposure for a short term to intense ultraviolet radiation can cause photokeratitis. Photokeratitis is sunburn on the eyes. It is the same as “welder’s flash” or “snow-blindness.” UV light burns off the outer layer of corneal cells, causing sensitivity to light, tearing and pain. Fortunately, permanent damage from photokeratitis is very rare.
Long-term effects of exposure to UV light include early cataracts, pingueculae, pterygia and benign and malignant lesions on the eyelids.
Cataracts form when the lens of an eye becomes less clear. Everyone eventually develops cataracts. Cataracts happen earlier in people with more UV exposure. When cataracts become a problem they can be removed surgically.
Pingueculae and pterygia are growths on the outer surface of an eye. UV light causes keratinization of the conjunctiva (the clear coating over the white of an eye). When this happens, the conjunctiva becomes yellow and elevated, which is called a pinguecula. If it grows onto the cornea, it is then called a pterygium. Most people in Arizona develop at least a mild pinguecula if they live here long enough. You may notice it if you look closely at the white of your eye in the mirror. It is that little yellow area to the side of your iris. Ptergia can be surgically removed if they are causing discomfort or interfering with vision.
Here in Flagstaff, we have thinner, cleaner air, which allows more UV radiation to reach us. For every 1,000 feet of increased altitude, there is a five percent increase in UV exposure. Snow, sand and water can also increase UV radiation up to four times. That is why you sunburn much quicker here in Flagstaff.
Protecting yourself from the sun is extremely important, especially in Flagstaff. Every time that you are going to be out in the sun, you should wear a hat with a brim, use sunscreen and wear your sunglasses. Sunscreen should be at least SPF 30, block both UVA and UVB and should be reapplied every two hours. When selecting sunglasses, pick a brand that you recognize like Smith, Maui Jim or Serengeti. These name brand sunglasses have to have the correct UV protection on them. Generic and imitation brand sunglasses may not block sufficient radiation.
So, when you’re outside biking, hiking, climbing, skiing, or on the river, remember to protect your eyes. FBN
Do we have a bio for Flag Eye Care
Larry Richardson, O.D. is an optometrist at Flagstaff Eye Care. For more information or an appointment with the Dr. Richardson, please call our office at 928-774-5093.
Page 13 photo caption:
Dr. David Caparrelli says he came to Flagstaff to be part of a great team at the Heart & Vascular Center Center of Northern Arizona.
Photo courtesy Flagstaff Medical Center
Written by By Nicholas Koshuta