People sometimes buy sunglasses the way they buy fashion accessories—a new pair every year with an emphasis on style. However, a proper pair of sunglasses is critical for protecting your eyes from the damaging effects of ultraviolet (UV) radiation. Sunglasses can be fashionable, but they also need to be functional.
Why You Need Sunglasses
- UV protection. The sun's UV radiation can cause cataracts, benign growths on the eye's surface, and cancer of the eyelids and skin around the eyes. UV radiation can also cause photokeratitis, sometimes called snow blindness, which is a temporary but painful sunburn of the eye's surface. Wide-brimmed hats and caps can only block about 50 percent of UV radiation from the eyes.
- Blue light protection. Long-term exposure to the blue and violet portion of the solar spectrum is a risk factor for macular degeneration, especially for people who are sun-sensitive.
- Comfortable vision. The sun's brightness and glare interferes with comfortable vision. Sunlight affects clear vision by causing people to squint and the eyes to water.
- Dark adaptation. Spending just two or three hours in bright sunlight can hamper the eyes' ability to adapt quickly to nighttime or indoor light levels. This can make driving at night more hazardous.
Wear sunglasses whenever you are outdoors, whether you are working, driving, participating in sports, taking a walk, running errands or doing anything in the sun.
Your sunglass lenses need to:
What You Need In Sunglasses
- block 99 to 100 percent of both UV-A and UV-B radiation;
- screen out 75 to 90 percent of visible light;
- be well matched in color and absorption and free of distortion and imperfection; and
- be gray to prevent any interference with good color vision.