Everything you Need to Know about Sunglasses

You’ve been thinking about buying new sunglasses, but the options are dizzying. So many frame choices. So many types of lenses. And what about UV protection, coatings, polarization and tints?

Style is a very personal choice. This guide won’t help you pick that perfect frame, but it will help you understand some of the options available to you when you’re shopping for new sunglasses. And you’ll find out how to care for them once you’ve made your choice. Let’s get started.

Why your eyes need sun protection

The single most important reason to wear sunglasses is to protect your eyes from the sun’s ultraviolet (UV) rays. Long-term exposure to UV rays has been linked to the development of serious eye issues, including macular degeneration and cataracts.

Protecting your eyes from the sun’s damaging rays is essential. To do so, wear sunglasses that block nearly 100% of UV rays (also called UV 400 protection) when you are outside during the day. Even when the skies are cloudy, wear sunglasses as a precaution. You can’t depend on the clouds to stop the UV rays from getting through.

Three forms of harmful UV radiation

Three types of UV radiation can damage your eyes. Each form has different characteristics and potential effects:

UVC rays

UVC rays pack the highest amount of energy and present the most danger to your eyes. Luckily, the Earth’s ozone layer prevents the majority of UVC rays from reaching the surface. If the ozone layer becomes depleted, however, UVC rays could easily cause serious health problems.

UVB rays

Some of the lower-energy UVB rays are also filtered by the atmosphere’s ozone layer. However, other UVB rays do get through. UVB radiation exposure is linked to several notable eye conditions. These include photokeratitis (snow blindness), pterygium (surfer’s eye) and pinguecula.

UVA rays

Of the three types of UV rays, UVA rays contain the lowest amount of energy. However, UVA rays can travel through your cornea to reach the lens and retina in your eye’s interior. In addition, excess UVA radiation is connected to the emergence of specific forms of cataracts and may play a role in macular degeneration.

UV radiation risk factors

Spending time outdoors puts you at risk of UV radiation-related eye conditions. However, your actual UV radiation dose depends on several factors.

• Geographic area – If you’re in a tropical region close to the Earth’s equator, you’ll receive an increased amount of UV exposure. As you get farther away from the equator, your risk decreases.
• Altitude above the Earth – You’ll receive greater UV exposure at higher altitudes.
• Specific setting – In expansive open spaces, you’ll receive greater UV exposure. This exposure is especially likely when you’re in proximity to sand, snow and other reflective surfaces. To illustrate, UV rays reflected off the snow can almost double your exposure.
• Time of the day (and year) – When the sun is at its highest daily position, you’ll receive more UV exposure. This time generally occurs from 10 a.m. to 2 p.m.
• Prescription medications – Several types of medications can heighten your sensitivity to UV radiation’s effects. Examples include sulfa drugs, diuretics, birth control pills, tetracycline and tranquilizers.

Buying tips from the experts

When you’re shopping for sunglasses, ensure that you choose a pair that provides excellent eye protection. To that end, follow these four tips from the American Optometric Association (AOA). 

• Buy sunglasses that filter out 99-100% of the UVA and UVB rays. Also, make sure that your sunglasses prevent 75-90% of visible light from reaching your eyes.
• If you wear contact lenses, know that only some types contain any degree of UV protection. Even while wearing your contacts, you’ll still need sunglasses to shield your eyes.
• Your sunglasses should follow your facial contours and should be situated close to your eyes. Well-fitting sunglasses should protect your eyes from all sides.
• Choose lenses with exactly matched colors. Also, ensure that the lenses don’t have any imperfections or distortions.

SEE RELATED: Different Types of Sunglasses: Styles, Shapes & Top Choices

Sunglasses design and construction

When you go pick out a new pair of sunglasses, you’ll have a lot of options. The brand and the style of the frame are just the first of several choices you can make. 

Frame construction

High-quality sunglass frames are made from durable, commonly available materials. Lightweight plastic frames shouldn’t slide down your face, and they are well-suited to different types of lenses. Metal frames add a distinctive touch to wire-rimmed sunglasses.

Lens types

If you’re in the market for quality sunglasses, you may have already made your sunglass frames selection. To determine which lenses are right for you, an optometrist will conduct a thorough eye exam.

Prescription sunglasses

If you don’t have 20/20 vision, prescription sunglasses present a stylish solution that combines vision correction with protection from the sun. An optometric lab will fabricate the glasses using your chosen frame style and the prescription information from your eye exam. When delivered, your prescription sunglasses will provide an eyewear solution along with an impressive fashion statement.

Non-prescription sunglasses

If you don’t need vision correction, you’re a candidate for non-prescription sunglasses. Also called plano sunglasses, these shades aren’t used to correct your vision. 

However, wearing plano sunglasses is a great way to keep your eyes safe from the sun’s harmful rays while accessorizing your wardrobe. Choose a style that compliments the shape of your face, fits your lifestyle and matches your personality. 

If fashion isn’t your priority, you may need sunglasses to enhance your performance in a specific sport. For example, a championship golfer may opt for eyewear that helps her see light and dark patterns in the grass in order to read the green better on a long putt.

Plano sunglasses are sold almost anywhere you go, from the convenience store down the street to massive online retailers to your local optometrist. Prices range from a few dollars for a generic pair to hundreds of dollars for exclusive designer sunglasses. The choices are nearly endless. Whichever sunglasses you choose, just make sure they have 100% UV protection.

Lens materials and treatments

Most eyewear manufacturers offer several different types of lens materials, each with its own characteristics. It’s possible to add extra coatings or treatments that compensate for a lens material’s downsides in most cases. 

Glass lenses

Relatively thick, heavy glass lenses deliver high-level optical clarity. They are also resistant to scratches. However, glass lenses can quickly be shattered or chipped. Besides, these lenses require an extra coating to reach the 100% UV protection threshold.

High-index plastic lenses

These high-tech lenses are very lightweight and will be thinner than comparable glass lenses. Most high-index lenses have 100% UV protection built in. Because the lens material is relatively soft and very reflective, these lenses require scratch-resistant and anti-reflective coatings.

Polycarbonate lenses

Highly impact-resistant polycarbonate lenses are 100% UV protective, and they’re lighter and thinner than every other lens type. However, polycarbonate lenses need a scratch-resistant coating in addition to a coating that decreases the lenses’ reflective characteristics.

Polarized lenses

By minimizing light reflection and glare, polarized sunglasses make colors appear brighter and more saturated. They can also make it easier to see objects below the surface of a lake or stream. 

The optometric lab can easily add polarization to the lens during the fabrication process. Note that polarized sunglasses can interfere with viewing LCD screens like those on many car instrument panels and smartphones. They are also not recommended when you are navigating on icy roads.

Lens coatings

Sunglass lenses frequently contain one or more special-purpose coatings. Adding multiple coatings will often increase the sunglasses’ price. 

• UV coating – Glass and plastic lenses often contain a UV coating. This extra layer doesn’t permit the sun’s damaging rays to reach your eyes.
• Anti-reflective coating – This coating is affixed to the backside of the sunglass lenses. The coating prevents light that’s hitting your face from reflecting off the back surface of the lenses.
• Scratch-resistant coating – A scratch-resistant coating aims to prevent scratches from damaging delicate sunglass lenses. This coating is applied to both sides of the lenses and is especially important for lightweight (and easily scratched) materials such as polycarbonate and high-index plastic.

SEE RELATED: How to find the best scratch-resistant sunglasses

Lens color

The color of the lenses is one of the primary characteristics of sunglasses. While certain tints are recommended for particular activities, lens color is mostly a personal preference and doesn’t affect how well the sunglasses protect your eyes from UV rays. 

Other than just liking the way you look in red (or blue or orange) lenses, why should you choose one color over another? Here are the most common lens colors and why you might pick one over another.

• Gray – The most neutral tint. It affects your color vision the least. Great for most activities.
• Green – Provides contrast and helps reduce glare and eye strain. Ideal for golf, tennis and everyday use.
• Red or rose – Block blue light, so they improve driving visibility while reducing eye strain. They enhance detail and increase depth of field. They work well for hunting, cycling and snow and water sports.
• Blue or purple – Deliver enhanced color perception. They compliment most skin tones and work well in foggy weather.
• Amber or brown – Increase contrast and heighten visual acuity. Perfect for most sports since they improve contrast against green grass and blue skies.
• Yellow, orange or gold – Improve visibility of objects, particularly in moderate- to low-light conditions. Excellent for both indoor and outdoor activities.

Mirrored lenses

Another option you’ll have when buying sunglasses is whether the outside of the lenses is mirrored. Mirrored lenses have a very thin coating that reflects light. Silvered aviator sunglasses are the classic example.

Today, you have a lot more choices than just silver: blue, orange, red, green and more. And — in some cases — gradients between two or more of these colors.

Mirrored lenses, especially bold colors and gradients, are primarily a style choice — they have a huge “cool” factor, no question — but they’re practical as well. The mirroring provides additional protection by reflecting even more light away from your eyes and reducing glare more than tinted lenses alone.

Privacy is another reason they’re popular. Mirrored lenses are more opaque than standard sunglass lenses, so they can lend a little additional anonymity.

RELATED READING: Has UV exposure been linked to eye cancer?

Taking care of your sunglasses 

To keep your sunglasses in good condition for years to come, it’s important to keep them clean, protected and in proper repair. 

Keep ’em clean

To clean your sunglasses: 

• Rinse them under slightly warm tap water to remove dust.
• Lightly rub a drop of no-lotion dishwashing liquid on the lenses and all parts of the frames.
• Thoroughly rinse to remove all the dish soap.
• Dry the sunglasses with a towel that’s clean and free of lint.
• Use a clean microfiber cloth to remove any remaining smudges.

When you’re on the go, clean your sunglasses with a microfiber cloth or disposable lens-cleaning wipe. Avoid cleaning your sunglasses with:

• Tissues
• Paper towels
• Terry cloth towels
• Shirt sleeves 

There’s a strong chance that using any of these items will scratch your sunglass lenses and negatively affect your vision.

Keep an adequate supply of lens-cleaning wipes, lens cleaner spray and microfiber cloths on hand. Local drugstores and discount stores are likely to carry these eyeglass-cleaning supplies.

READ MORE: Sunglasses Diagram

On your face or in the case

When you’re not wearing your sunglasses, always store them in a protective, hard-shell sunglasses case. This practice will significantly reduce the risk of damage and help ensure that you get years of service from your quality eyewear.

If there’s a bend or a scratch

If your sunglasses get scratched or the frames get damaged, it may be possible to fix them yourself, but that can also lead to further problems. In most cases, it’s best to consult an optical store or specialty repair shop that knows the brand and stocks the right replacement parts. 

Start with an eye exam

Before purchasing sunglasses, schedule an eye exam with an eye doctor near you. You might be considering non-prescription sunglasses, but even though you may see well enough to pass a driver's vision screening without glasses, you might be able to see significantly better with prescription sunglasses. Only your eye doctor knows for sure.