How Do Sunglasses Work? Why Do They Shield Our Eyes From the Sun?

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Your favorite pair of sunglasses are more than just a fashion accessory. They also protect your eyes from harmful UVA and UVB rays! Whether you’re an avid snowboarder, sand volleyball player, or just enjoy walks outside, you should know how your sunglasses are protecting your eyes.

67% of the custom sunglasses we sell at Quality Logo Products are ordered in the summer when the sun is at its harshest. Our customers ask us all the time if the sunglasses they buy will actually protect their eyes. They want to know how those lenses work.

Here’s the answer! It’s time to learn how sunglasses work and why your eyes are protected thanks to a cool pair of shades.

What Are the Different Types of Sunglasses Lenses?

There are several types of lenses that are ideal for different purposes, whether it be driving, convenience, or extra bright conditions. Discover how the different types of sunglasses lenses work, and which one is right for you.



Tinted from top-down to shield eyes from overhead sunlight, gradient lenses also allow more light through the bottom half.

Mirror Coated

Mirror Coated

Aside from making you look like a secret agent, mirror-coated lenses are ideal for extra bright conditions.



Also called “transition lenses”, the tint of photochromatic lenses automatically adjusts when exposed to sunlight.



When you choose prescription sunglasses lenses, the days of clip-on or magnetic sun lenses are over. You can purchase lenses with your prescription tinted to any darkness you want.

How Are Sunglasses Polarized?

Sunglasses are polarized by laminating a special chemical in a vertical pattern on lenses. Polarized sunglasses are great at protecting your eyes from sun damage because they block horizontal light and glare. Think about the discomfort caused by the blinding glare off the hood of an oncoming car, or insanely bright snow on a sunny day. With a pair of polarized sunglasses, you won’t have to worry about discomfort or distorted vision from glare.

As you can see, polarized sunglasses can be especially useful for fishing, snowboarding, or driving because of the way they block horizontal light. On especially sunny days, these shades will make these activities safer and more fun!

Why Are Sunglasses Dark?

Sunglasses are dark because the tint cuts out a portion of the visible light, but you don’t necessarily need the darkest lenses available to protect your eyes. More than 40% of Americans believe that darker sunglasses provide more UV protection, but that’s a myth. Clear and transparent lenses can also provide UV protection.

The most popular tint color for sunglasses is gray. Gray is a neutral color that doesn’t distort colors and can also reduce brightness and glare. On cloudy days, amber or brown tinted sunglasses will increase contrast and brighten your vision. Consider yellow or orange lenses for foggy or low-light conditions.

Different tints provide different benefits and are best suited to a variety of activities, but regardless of the tint you like best, you should always have lenses with UV protection.

How Do Sunglasses Protect Your Eyes?

Sunglasses protect your eyes by acting as a barrier that reflects UV rays. Sunglasses are the equivalent of sunscreen for your eyes. Aside from being a beach accessory, they protect your eyes from the sun’s harmful light rays. Experts recommend that your shades protect your eyes from at least 99% of UV rays.

As you can see, the sun’s rays can penetrate through different areas of your eyeball. UVA rays can reach all the way to the retina in the back of your eye, while UVB rays reach the cornea in the front of the eye. Sunglasses prevent these rays from penetrating your eye, saving you from potential damage or vision loss.

Did you know?

UV rays are the harshest when the sun is high in the sky between 10am and 2pm.

What Are the Different Types of Sunlight?

While the sun has many different rays, UV rays are the most harmful to our eyes. UVA and UVB rays are the two basic types of sunlight that reach earth’s surface. Sunglasses are designed to reflect both UVA and UVB rays.

UVA Rays

UVA rays are 30 to 50 times more prevalent than any other type of light, and account for 95% of UV radiation.

UVB Rays

UVB rays are more prevalent at higher altitudes and can even penetrate on cloudy days. You can thank UVB rays for painful sunburns.

Visible Light

Visible light is what gives objects color. This type of light is not filtered by sunglasses and does not pose health risks.

Did you know?

Wearing a wide-brimmed hat can reduce your eye’s exposure to UV rays by up to 50%!

When shopping for sunglasses, you should look for lenses that block 100% of UV rays. It’s important to remember that not all lenses block 100% of radiation. For extra UV protection, consider large lenses or a close-fitting style of sunglasses to safeguard the skin around your eyes.

What Are the Risks of UV Exposure?

As you’ve learned, UV rays are harmful to our eyes because they can cause several vision problems both short and long term. Without a pair of sunglasses handy, you could be at risk for the following health concerns.

Long Term Risks

Short Term Risks

  • Cataracts
  • Macular Deeneration
  • Pinguecula
  • Photokeratitis
  • Cancer of the eye
  • Age related Macular Degeneration

Short Term Risks

  • Swollen eyes
  • Bloodshot eyes
  • Hypersensitivity to light

Did you know?

More than 1 in 3 adults have experienced symptoms from unprotected UV exposure.

How Often Should You Replace Your Sunglasses?

How Often Should You Replace Your Sunglasses?

You shouldn’t only replace your sunglasses after they’ve gotten scratched or lost. In fact, the UV protection on your sunglass lenses can deteriorate over time, meaning you should replace your sunglasses around every two years with heavy use.

In order to properly protect your eyes, it is important to replace your sunglasses to reduce the risks of UV radiation. If you’re wondering if it is safe to wear an old pair of favorites, you can take them to a local eyeglass retailer where they can test UV protection levels.

Why Should You Wear Sunglasses?

You should wear sunglasses because they protect your eyes, reduce strain and sensitivity, and can be a stylish accessory. According to The Vision Council, “if the average U.S. adult spent just 30 minutes wearing a pair of sunglasses with adequate UV protection during the day, their eyes would gain nearly 183 hours of UV-free time over the course of a year.”

Not only do sunglasses protect your eyes from sun-related health problems, but they can shield your eyes from the elements like dirt, sand, water, and wind. If you’re participating in outdoor summer sports or simply running afternoon errands, having a good pair of sunglasses handy can make all the difference.

Sunglasses for Any Occasion

Sunglasses for Any Occasion

Promotional sunglasses are a bright addition to any event. From aviator to polarized lenses, these stylish giveaways come in a variety of eye-catching colors!

The Bottom Line

Protect your eyes and look good doing it with the perfect pair of sunglasses. Whether you have one favorite pair or multiple styles for different occasions, it is important to wear them outdoors as much as possible.


American Optometric Association (2019, May). UV Protection. Retrieved May 8, 2019, from

Bedinghaus, T. (2019, March 14). What to Know About Polarized Sunglasses. Retrieved May 8, 2019, from

Bedinghaus, T. (2019, April 30). Sunglasses: Does Color Matter? Retrieved May 8, 2019, from

Heiting, G. (2019, April). UV and Sunglasses: How to Protect your Eyes. Retrieved May 8, 2019, from

Jones, A. (2019, February 2). Visible Light Spectrum Overview and Chart. Retrieved May 8, 2019, from

MacMillan, A. (2017, May 11). You May need to Replace Your Sunglasses More Often Than You Think. Retrieved May 8, 2019, from

Morgan, E. (2018, February). Your Guide to Prescription Sunglasses. Retrieved May 8, 2019, from

Olympic Eyewear. (2012, June 8). Different Types of Sunglass Lenses. Retrieved May 8, 2019, from

St. John, E. (2017, April 24) Effects of Visible Light Radiation. Retrieved May 8, 2019, from

The Vision Council. (2016). Share your Sight: Using Shades for Protection and Style. Retrieved May 8, 2019, from

Travel Star. (2014). Why to Protect Your Eyes While Traveling. Retrieved May 8, 2019, from

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