Step-by-step

1. 1. UV Damage and Your Eyes

   Much more than a celebrity fashion accessory, sunglasses are an essential tool in protecting your vision. Studies show that exposure to the sun’s ultraviolet (UV) rays can harm the lens and cornea of the eye, leading to problems -- like cataracts and macular degeneration -- that can impair vision. And the thin skin around the eye and the eyelid itself are especially vulnerable to skin cancer and to sun-induced signs of aging. Dr. Gail Royal, an ophthalmologist in Myrtle Beach, S.C., admits that she sometimes appeals to her patients’ vanity when she discusses the importance of proper sunglass use. “I’ll point out that sunglasses will protect not just against basal cell and squamous cell carcinomas and melanoma,” she says, “but also against the formation of wrinkles like crow’s-feet and the unsightly thickening of the skin that can sometimes be caused by UV exposure.”

   Here’s how to choose a pair of sunglasses that will safeguard your eyes and help your skin care regimen.

2. 2. Look for Complete UV Protection

   Whether you spend $200 for a pair of designer sunglasses or buy one off the drugstore rack for $20, both can do an equally good job of blocking harmful ultraviolet rays. Look for a label or sticker that says the lenses block 99 or 100 percent of UVA and UVB rays. Sunglasses with full protection might also say something like, “Lenses meet ANSI Z80-3 blocking requirements,” or “UV 400 protection.” Sunglass boutiques sometimes remove these labels or stickers for a more attractive display. Chances are the shades provide full UV protection; just be sure to ask.

3. 3. Color Counts If You’re Behind the Wheel

   It may seem logical that a darker lens would do a better job of blocking the sun’s harmful rays than a lighter lens, but that turns out not to be the case. The coating that blocks UV radiation is clear, so shades of any hue are equally effective at filtering those rays. Yellow or rose-tinted lenses can, however, make it difficult to distinguish changes in traffic lights. Gray, green and brown lenses minimize color distortion.

4. 4. Focus on Fit

   To block the light that hits your eye from the sides, choose wraparound frames. Your next best bet? Sunglasses with large lenses and wide temples, like the iconic oversized frames Audrey Hepburn wore in Breakfast at Tiffany’s. Whatever the style, frames should fit snugly on your nose and ears without pinching or rubbing, but not so close that your eyelashes hit the lens.

5. 5. Choose Polarized Lenses If You Water Ski, Surf or Fish

   Polarized lenses reduce glare by filtering out the reflected light that bounces off water. Polarization, however, has nothing to do with UV light absorption, so check the label to make sure they provide maximum UV protection. Keep in mind that, when you’re wearing polarized lenses, it may be difficult to read your cell phone, GPS device or a liquid-crystal display on a dashboard or an ATM machine.

6. 6. Make Sunglasses a Daily Habit

   Like sunscreen, sunglasses should be worn whenever you’re outdoors, year-round. “Just as we’ve learned that you can get a really nasty sunburn on an overcast, hazy day,” says Royal, “you’re exposing your eyes to damaging UV rays on these days too.” So, keep a pair of sunglasses in your purse as part of your beauty routine, along with a small tube of sunblock, and your favorite new coral, peach or pink lip gloss.