While sunglasses may be a fashion accessory, their purpose is much more important than that. Long-term exposure to ultraviolet (UV) radiation in sunlight has been linked to cataracts, retinal complications, and eye growths, including cancer. There are two types of UV radiation in sunlight—UVB and UVA. UVB radiation is considered more dangerous to the eyes and skin than UVA, but not all sunglasses filter either type of radiation. Here are 4 key factors to keep in mind when choosing sunglasses:
UV Absorption
Both plastic and glass lenses absorb some UV light, but manufacturers can improve UV absorption by adding chemicals to the lens or by applying special lens coatings.
Look for sunglasses that block 99 percent or 100 percent of UVA and UVB light. If a manufacturer’s label says “UV absorption up to 400nm,” this is equivalent to 100 percent UV absorption.
Do not assume polarized and darkened lenses offer UV protection. Polarized lenses cut reflected glare, but that has nothing to do with UV light absorption. They still must be labeled for 99% or 100% protection of all UV light. If they’re not, your eyes are actually exposed to more light than if you didn’t wear sunglasses because darkened lenses cause your pupils to dilate.
Quality
To judge the quality of nonprescription sunglasses, the American Academy of Ophthalmology recommends that you look at something with a rectangular pattern, such as a floor tile. Cover one eye as you hold the glasses at a comfortable distance. Move the glasses slowly up and down, and from side to side. If the lines stay straight, the quality of the lenses is fine. If the lines wiggle, especially in the center of the lens, the quality is poor.
Fit
It’s also important to find sunglasses that fit correctly. If the glasses have gaps they won’t be as effective in preventing UV rays from reaching your eyes. Look for a pair that fits snugly to your face without touching your eyelashes, and that aligns with your brow.
Wrap-around sunglasses are a good option for added protection from all angles. They are particularly useful If you suffer from seasonal allergies and need to protect your eyes from substances like pollen.
Lenses
Sunglass lenses may be made from shatterproof glass, plastic, or polycarbonate plastic. All sunglasses must meet impact safety standards set by the Federal Food and Drug Administration (FDA). While no lens unbreakable, plastic lenses are less likely than glass lenses to shatter when hit by an object. Polycarbonate plastic sunglasses are especially tough, which is useful for sports and recreational activities. However, they scratch easily so look for ones with scratch-resistant coatings if you choose to buy polycarbonate lenses.
We recommend wearing sunglasses that fully protect your eyes every time you step outside.
And if you suspect you need prescription sunglasses, one of our eye specialists will be happy to help you with a comprehensive eye examination so that you have the correct prescription.
Baptist Eye Surgeons is an ophthalmological practice dedicated to providing quality eye care to patients whose needs range from routine comprehensive eye examinations to complex eye surgeries. To request an appointment or get directions to our Knoxville and Morristown locations, visit our website. Call us at 865-579-3920 for more information, or visit us online to schedule an appointment.
