While we've been told for many years now how important it is to protect our skin from the harmful effect of the sun's rays, do you know how important it is to protect our eyesight from the sun as well?
Ultraviolet light, long known to cause skin cancer, can also be absorbed by your eyes, causing a number of chronic eye diseases, such as cataracts, age-related macular degeneration, pterygia (tissue growths on the eye), photokeratitis (a temporary sunburn on the eye, also called snowblindness) and skin cancer on tissues surrounding the eye.
Both UVA and UVB rays penetrate the Earth's atmosphere and wreak havoc on unguarded eyes. UVB rays are higher energy than UVA and are the ones primarily responsible for causing skin cancer. They are mostly absorbed by the cornea and lens, but they can also penetrate deeper and cause damage. UVA rays are lower energy waves. These are the rays that make you tan, but they also contribute to skin cancer and they penetrate much deeper into your eyes to the retina.
The most effective and simplest way to protect your eyes from harm is to wear a hat and sunglasses. Choose sunglasses with 99-100 percent protection from both UVA and UVB rays. These glasses can be found in any price range. Choose large lenses to cover the most area around your eyes. Contact wearers who use lenses with UVA protection still need to wear sunglasses to protect eye areas not covered by their lenses.
Since typical sunglasses don't protect eyes completely, you may want to consider wrap-around styles or sunglasses made to wear over prescription glasses. An optician can test your lenses to make sure they are offering you appropriate protection against UV rays.
Your hat will protect you from rays that sneak in over the tops or around the sides of your glasses. Choose a hat with a brim or visor to provide extra protection.
It is especially important for young children and teens who tend to spend a great amount of time outdoors to protect their eyes. In fact, experts say nearly 50 percent (or more) of our lifetime exposure to UV rays may occur by age 18, given that many children spend significantly more time outdoors than the average adult.
During the summer, the strongest UV rays occur between 10 a.m. and 2 p.m. and particular care should be taken to protect the eyes during that time.
Some risk factors for UV exposure:
- Geographic location. UV levels are greater in tropical areas near the earth's equator. The farther you are from the equator, the smaller your risk.
- Altitude. UV levels are greater at higher altitudes.
- Time of day. UV and HEV levels are greater when the sun is high in the sky, typically from 10 a.m. to 2 p.m.
- Setting. UV and HEV (high-energy visible radiation) levels are greater in wide open spaces, especially when highly reflective surfaces are present, like snow and sand. In fact, UV exposure can nearly double when UV rays are reflected from the snow. UV exposure is less likely in urban settings, where tall buildings shade the streets.
- Medications. Certain medications, such as tetracycline, sulfa drugs, birth control pills, diuretics and tranquilizers, can increase your body's sensitivity to UV and HEV radiation.
The bottom line is, have fun outdoors, but do make protecting your eyes a priority. Always wear sun protection. When it comes to your eyes, it's not worth the risk.
Dr. Peter J Blackburn is associate professor of ophthalmology in the University of Kentucky College of Medicine.