We all know that slathering on sunscreen lotion is a must during the scorching summer season, but did you realize that ultraviolet rays are just as damaging to your eyes as they are to your skin? Yet according to a survey conducted by the American Optometric Association (AOA), only 49 percent of Americans said UV protection was the most important factor when purchasing sunglasses -- while price and style of sunglasses were top considerations. Research shows that exposure to small amounts of UV radiation over several years can cause cumulative damage to the retina -- and that damage may lead to cataracts and macular degeneration in later years. In fact, macular degeneration is the leading cause of blindness in our nation, according to the AOA. We spoke with Andrea Thau, O.D., spokesperson for the AOA for tips on protecting your eyes and choosing the best sunglasses.

Sun Sensitivity

Do you have fair skin and light eyes? If so, the sun poses an even greater risk to your eyes. "The fairer you are and the lighter your eye color, the more sensitive you are to sun the sun's harmful UV rays," says Dr. Thau. "People with darker skin might be less susceptible, but they still shouldn't take the risk of not protecting their eyes."

Size Matters

When it comes to the size of the lens, bigger really is better, says Dr. Thau. "A large lens protects more areas of your eyes -- like the skin around the eyelids, which is very thin, delicate, and susceptible to skin cancer." Another bonus of super-size glasses? "They prevent wrinkles, too" she says.

Pricier Isn't Better

Good glasses aren't measurable by price tag. What makes a pair solid is that it shields your eyes from both visible light and ultraviolet radiation -- and the latter trumps all other considerations. "Look for 99 or 100 percent UVA and UVB protection," says Dr. Thau. But beware that some flea-market finds might promise protection they don't actually offer. "If the sunglasses aren't labeled," she says, "have them tested at the place where you're purchasing them or take them to an optometrist."

Tint Considerations

The AOA recommends buying sunglasses that have a uniform tint (instead of darker in one area than another). And if she had to choose one color lens over all others, Dr. Thau would opt for gray. "Gray renders colors the most natural and doesn't distort them," she says, which is an important consideration when driving.

Do Transitions Make the Cut?

In recent years, transitional lenses -- those that automatically adjust their level of tint to changing light conditions -- have been a trendy option for sunglasses wearers. But do they stand up to our experts' strict standards? They usually offer excellent UV protection, says Dr. Thau. "The only drawback to these lenses is that they don't get dark behind the windshield of a car; since most windshields block out the light that is needed to make the lens react -- that makes them less effective."

Dark Lens Danger

Dark lenses are ideal, but choose them carefully. They should be dark enough that your eyes can't be seen through them, but should have UV protection. Dr. Thau cautions that dark lenses without UV protection may actually cause more harm to your eyes than if you were wearing no glasses at all. Why? "A dark lens that doesn't block UV radiation makes your pupils dilate and opens the eye to radiation exposure," she says. When you don't wear sunglasses, the pupil naturally constricts to limit UV radiation.

Sun-Proof Your Contacts

While it may seem that wearing a lens atop your cornea would shield your eyes, Dr. Thau warns that contacts can make your eyes more sensitive to light, so sunglasses should be a top priority for contact-wearers. "High-quality sunglasses give you a two-for-one special: They block the debris that can get underneath the lens, and they protect against UV rays." In addition to wearing sunglasses vigilantly, Dr. Thau suggests that lens wearers purchase brands with built-in UV protection. "Although the lens doesn't completely cover your eyeball and lid, it extends past the cornea into the white of the eyes -- so it does shield the eye from sunlight."

Seek Cover in Clouds

Just as you're still at risk for sunburn on a cloudy day, you don't have to see the sun in order for it to harm your eyes. Even on overcast days, you need a lens to shield you from UV rays so Dr. Thau suggests investing in two pairs of glasses -- one with dark lenses for bright sun and another with a lighter lens for overcast days -- both with UV protection.

Kids Need Glasses, Too

Though it's never too late to protect your eyesight, an early start does the most good. "Studies show that the majority of damage occurs in childhood and you pay the price later in life," says Dr. Thau. Though high-quality sunglasses for children can be a tad pricey, she advises that parents consider it an investment in their kids' long-term eye health. "Choose lenses that are made from polycarbonate -- it's a safe material that provides excellent impact protection."