Mireya Acierto via Getty Images
There are multiple factors to consider when choosing a pair of sunglasses.Sunglasses are a much-loved accessory, but they also play an important role in promoting our eye health ― or they should, anyway.
“Many consumers may look for stylish sunglasses to make a fashion statement, however fashion means little if those brand-new sunglasses fail at their most important purpose — protecting the eyes from the sun’s rays,” said William T. Reynolds, an optometrist and president of the American Optometric Association. “However, according to the AOA’s American Eye-Q survey, only half of people that purchased sunglasses check the UV ray protection level before purchasing and only half wear sunglasses primarily to protect their eyes from sun damage.”
Advertisement
But if you want an effective pair of sunglasses, do you have to shell out for the expensive designer pairs that cost hundreds of dollars? Or can cheap sunnies do the job as well?
We asked Reynolds and other experts to explain what makes sunglasses effective and what to look for when choosing a pair.
The main purpose of wearing sunglasses is to protect your eyes from the sun’s ultraviolet rays, which can harm your vision and cause serious health issues like cataracts and macular degeneration.
“If you are getting tinted lenses, make sure they are 100% UV protected, with both UVA and UVB,” said Peggy Denofa, an optician with ReFocus Eye Health. “If they are just tinted they will cause your pupil to dilate and allow more destructive UV light through to damage the eyes.”
Advertisement
The best way to verify the level of UV protection is to bring your sunglasses to your next appointment with an eye care professional. But if you haven’t already purchased the glasses, you should look for specifics on the product label.
“In terms of sun protection, you want to find a sunglass that protects from UVA and UVB rays, which is called a UV 400 lens,” said Nicole Romito, vice president of e-commerce and marketing at the independent eyewear company Krewe. “This is the industry standard for ultraviolet ray protection and blocks 100% of UVA and UVB transmission.”
The term UV 400, which isn’t regulated by the government, is used to describe lenses that block radiation equal to or shorter than 400 nanometers, which is the distance needed to protect against both UVA and UVB rays.
More expensive sunglasses generally offer higher quality lenses with true UV protection, according to Reynolds.
“However it is very easy to find inexpensive glasses that offer 100% UV protection,” he added. “Just don’t assume all cheap sunglasses provide this level of protection, even if a sticker on the lenses says, ‘blocks UV.’”
Advertisement
“When looking at sunglasses in particular, one of the things you should always look for is a lens that blocks UV rays and a lens that is polarized,” said Jordan Kassalow, an optometrist at Farkas, Kassalow, Resnick & Associates and Pair Eyewear consultant. “The UV ray protection works as a sort of sunscreen for your eyes while polarized lenses help filter and block reflected light which makes driving and outdoor activities easier and safer.”
Polarized lenses and UV protection are separate considerations, so although sunglasses with polarized lenses often block UV rays, that’s not a given.
“Most expensive frames have polarized lenses, which block out reflective light, like a wet road,” Denofa said. “Polarized lenses also cut more glare than just a tinted lens.”
Basically, polarized lenses filter out horizontal light waves bouncing off surfaces like water, snow or glass. That’s why they’re helpful for situations like driving or skiing, when harsh glares can be dangerous.
UV protection and polarization aren’t the only factors in the cost and quality of sunglass lenses.
“There are many materials that lenses can be made of and range in terms of quality and clarity, and a lot of different types of coatings for these lenses,” Romito explained. “Sunglasses with high clarity lenses will cost more, but will make wearing them much more comfortable for your vision.”
Advertisement
She also noted that specialty lens coatings like mirror, anti-reflective, scratch-resistant and hydrophobic can add to the cost.
But that doesn’t mean you have to shell out an enormous amount of money for good-quality lenses. Cheaper sunglasses can be effective, especially when you’re buying from a trusted optical brand. Reynolds offered some additional guidelines for choosing a pair of sunglasses.
“Pick lenses that are perfectly matched in color and are free of distortion and imperfection,” he advised. “Lenses should also have a uniform tint, not darker in one area from another. The AOA suggests a gray tint, which is particularly helpful when driving as it offers the best color recognition.”
Reynolds also recommended looking closely to make sure the lenses are distortion-free by looking through them at a straight line in the distance, like the edge of a door.
“Slowly move the lens across the line,” he said. “You’ll see imperfections if the straight edge distorts, sways or curves. Your lenses need to block light so try them on in front of a mirror. Now, if you see your eyes too easily, the lenses probably aren’t dark enough. The same test doesn’t work on photochromic lenses, though, since these change color with light.”
Advertisement
The materials used in the construction of the frame can also affect the cost of a pair of sunglasses.
“Expensive frames are made with stainless steel or titanium, which are stronger metals,” Denofa said. “Those metals also will not break your skin out like a cheap frame that is usually made of nickel. In fact, many people are allergic to nickel. Cheap plastic frames are hard to adjust and keep adjusted — also, the hinges are not as strong. The quality just isn’t there.”
Romito echoed this sentiment, noting that some plastics are fragile and can crack or break easily, and that metal quality affects durability.
“A lower-price sun frame will use metal alloys that are a blend of many metals like brass and copper in order to reduce cost, which are soft metals and are easily deformed,” she said. “You can also do different things with shape and color depending on the material.”
Reynolds, however, said that the material of the frame isn’t terribly important, as far as he’s concerned.
Advertisement
“But you should find a frame that fits close to the eyes and contours to the shape of the face, in order to prevent exposure to UV radiation from all sides, even behind,” he said.
“When it comes to glasses and sunglasses, a higher price tag does not necessarily mean you’re getting a better product,” Kassalow noted. “So long as the glasses or sunglasses meet your particular needs and offer protection from potential sun damage, the price of a pair of glasses or sunglasses has relatively little to do with the quality of the product.”
He noted that a small number of companies have dominated the eyewear industry for a long time and kept prices artificially high. Direct-to-consumer brands like Pair Eyewear and Warby Parker now bypass traditional design and manufacturing channels and offer lower prices.
“What many people don’t know about glasses and sunglasses is that the vast majority of brands do not actually make and manufacture their own eyewear and are instead licensed by a third-party vendor,” Kassalow explained. “So what you really are paying for is marketing and branding as opposed to the actual frames.”
Finding the most effective sunglasses is a matter of choosing the right lenses and making sure the frame fits your face. While shades that meet those requirements don’t have to be expensive, your choice of style, branding and any additional features may drive up the price
Advertisement
Whatever your personal preference is on that front, the most important thing is to actually wear your sunglasses on a consistent basis.
“While people are often much more diligent about protecting their eyes from UV rays during the summer, they tend to neglect this task during the winter, even though the sun’s rays can be more harmful during the winter months,” Reynolds noted. “You should wear sunglasses whenever you are outdoors, whether you are working, driving, participating in sports, taking a walk, running errands, or doing anything in the sun. Overexposure to the sun can lead to irritating and painful short-term effects on the eyes.”
A pair of sunglasses seems so simple -- it's two pieces of tinted glass or plastic in some sort of plastic or metal frame. How much more straightforward can something get? It turns out that there are many different things you can do with two pieces of glass, and these things can have a big effect on you when you use the lenses. As you will see in this article, there really is a difference between the various sunglasses you'll find out there.
There are four things that a good pair of sunglasses should do for you:
Advertisement
Ultraviolet (UV) light damages the cornea and the retina . Good sunglasses can eliminate UV rays completely.
When the eye receives too much light, it naturally closes the iris . Once it has closed the iris as far as it can, the next step is squinting. If there is still too much light, as there can be when sunlight is reflecting off of snow, the result is damage to the retina. Good sunglasses can block light entering the eyes by as much as 97 percent to avoid damage.
Sunglasses provide protection from glare. Certain surfaces, such as water, can reflect a great deal of light, and the bright spots can be distracting or can hide objects. Good sunglasses can completely eliminate this kind of glare using polarization (we'll discuss polarization later).
Certain frequencies of light can blur vision, and others can enhance contrast. Choosing the right color for your sunglasses lets them work better in specific situations.
When you buy a pair of cheap sunglasses, you often give up all of these benefits and can even make things worse. For example, if your sunglasses offer no UV protection, you increase your exposure to UV rays. The cheap sunglasses block some of the light, causing your iris to open to allow more light in. This lets in more of the UV light as well, increasing the damage UV light can cause to the retina.
So there is a difference. Buying the right pair of good sunglasses for the conditions in which you use them gives you maximum protection and performance.
The sidebar shows some of the top sunglass manufacturers. Manufacturers of other products sell sunglasses, too. From Nike and Timberland to Gucci and Kenneth Cole, many big brands include sunglasses among their product lines. Many sunglass manufacturers make huge claims about the features and special qualities of their products. Prices can range from less than $20 up to several hundred dollars depending on the features and the name.
Did You Know?
Scratch-resistant and UV blocking glasses were developed from NASA welding technology. Learn more about cool NASA innovations in this interactive animation from Discovery Channel.