We often buy sunglasses the same way we buy fashion accessories: a new pair every spring with an emphasis on the latest trends. But, being in the sun should always mean taking precautions against damaging ultra-violet (UV) radiation.
Sunglasses aren’t just fashion accessories. They are a necessary protection for the eyes.
Most people know that sun can damage your skin, but many are unaware that the sun’s rays can damage the eyes.
To correctly shield the eyes, the right type of sunglasses must be worn, especially since wearing the wrong type can cause more damage than not wearing glasses at all.
The eyes are susceptible to being burned by sun-rays. The cornea, lens, and retina are all vulnerable to overexposure of ultraviolet (UV) rays.
Over time these UV rays -invisible to the human eye can harm the eye if left unprotected. Workers who are heavily exposed to sunlight should protect their eyes with UV-blocking sunglasses.
Sunglasses help in two important ways. They filter light and protect the eyes from damaging UV rays. Long-term exposure to UV rays can lead to cataracts, macular degeneration, or skin cancer around the eye-lids. Sunglasses should be worn outdoors to protect the eyes.
Buying Lenses: What to look for to ensure protection
Don’t be misled by faulty UV claims. To make sure that UV labels are accurate, buy sunglasses where there is equipment available to check the lenses’ UV protection capabilities, or ask your optometrist for his or her opinion on a specific purchase.
Check lenses to be sure the tint is uniform, not darker in one area than another.
With gradient lenses, the tint should lighten gradually from top to bottom. Sunglass tints used for driving should be gray to allow proper traffic light recognition.
Ensure that lenses are distortion free. Hold the glasses at arm’s length. Look through them at a straight line in the distance. Slowly move the lens across the line. If the straight edge distorts, sways, curves or moves, the lens has imperfections.
To be sure the lenses block enough light, try them on in front of a mirror. If you can see your eyes easily through the lenses, they probably are not dark enough. Note: this test does not apply to photochromic (light-sensitive) lenses.
Look for sunglasses that:
Block at least 99 percent of both UV-A and UV-B radiation.
Screen out 75 to 90 percent of visible light.