Your budget might rejoice at the $5 spotted sunnies you snagged from the cute seaside shop, but your eyes might not be so thrilled. That's because cheap sunglasses can do great harm to your eyes, says Ming Wang, MD, PhD, an opthamologist from Nashville, Tennesse.
"Cheap sunglasses may not provide necessary ultraviolet (UV) protection," Dr. Wang says. "Certain inexpensive sunglasses may allow the harmful UV light to penetrate and expose the delicate structures of the eye."
When you're outside in the sun without sunglasses, your eyes instinctively squint and your pupils constrict to limit the amount of light that can get in. When you put on a pair of tinted lenses, you fool your eyes into dilating, or staying more open. That lets a greater amount of UV light in, light that can ultimately be very damaging if the lenses do not have a built-in UV filter.
UV exposure from the sun has been shown to cause health problems, including sunburn of the eyes, cataracts, macular degeneration, and even certain types of skin cancer. Another condition called surfer's eye leads to bumps or growths on your eye or eyelids. It's believed to be caused by dry eye and exposure to sun, wind, and dust, all things surfers are likely to encounter.
"Additionally, sunglasses with basic 'tinted' lenses may not do anything to help with harsh glares that can interfere with comfortable vision and the ability to see clearly," says Diego de Castro, director of global brand strategy for Maui Jim. "Glare is problematic with 25 percent of daytime crashes being attributed to glare."
Dr. Wang adds that less expensive sunglasses may also have lower optical quality, which means what you look at may appear distorted or non-uniform in color saturation.
"While this is not inherently harmful," he says, "it can reduce enjoyment of the activities you are participating in."
Three things to look for when purchasing sunglasses
A dark lens is not an indicator of polarization or UV filter, so even looking for the darkest shades at the store won't do you any good. You need to see the magic words—a guaranteed UVA/UVB block.
"Sunglasses sold in the U.S. should meet a minimum standard, which is established by the American National Standard Institute," Dr. Wang says. "This requires them to be impact resistant, block 99 to 100 percent of UVA and UVB light and 75 to 100 percent of visible light."
So does that mean all inexpensive sunglasses doom your eyes to damage? No, many inexpensive brands meet the criteria for high-quality UV protection. What it does mean, however, is that you need to be more diligent when you're shopping for sunglasses. The protective factors are just as important as the cute pattern.
Greg Bullock, marketing manager with TheraSpecs, suggests people keep three important characteristics in mind when shopping for your next set of shades:
- Polarization: This cuts down on glare, an important factor when boating or driving.
- UVA/UVB protection: This blocks UV rays and prevents sun damage to your eyes and the delicate skin around them. The higher the better. Look for shades that promise UV protection of 99 to 100 percent. A UV 400 rating means the glasses block all UVA and UVB rays, too.
- Impact resistant lenses: These break-resistant lenses protect your eyes from injury.