When You Should Wear Sunglasses and How to Tell If They’re Working

When You Should Wear Sunglasses and How to Tell If They’re Working

When the sun is shining brightly, it’s easy to remember to wear sunglasses.

According to a recent survey, more than 70 percent of adults wear their sunglasses when the sun is too bright.

But what about the rest of the time?

Well, according to statistics, we’re not doing so well on cloudy days. When the snow is blowing, less than a third of consumers wear sunglasses.

Why would that be a problem?

We explain in this post—plus, we help you determine whether your sunglasses are doing a good job of protecting your eyes.


Wear Sunglasses to Reduce the Sun’s Glare

Sunglasses, as we know them, first started to show up in the early 1920s. British chemist Sir William Crookes was the first to develop lenses that blocked UV light using an element known as cerium. Movie stars were quick to adopt his eyewear, which fueled its popularity.

Sunglasses came onto the American market in 1929, when American entrepreneur Sam Foster started selling them on the boardwalk in Atlantic City, New Jersey. He used a different technology for his, employing celluloid as the main material, which allowed him to mass produce his products.

Then in 1930, the U.S. Army came out with aviator sunglasses for Army Air Corps pilots. These originally had green-tinted lenses, but they were later changed to rose as the red color better protected the pilots’ eyes from the sun’s glare.

Back then, people didn’t buy sunglasses to protect their eyes from damaging ultraviolet (UV) rays. They wore them for one of two reasons: either to protect their eyes from the bright sunlight or to disguise themselves in public. Celebrities liked them for the second reason, as they thought they helped limit fans' ability to recognize them.

Everyone else wanted protection from bright sunlight. To that end, in 1937, inventor Edwin H. Land—the man behind instant photography and the Polaroid system—came out with polarized lenses for sunglasses. He had been working with polarization for years, mainly in the realm of photography. Once he perfected the technology, he applied it to sunglasses to better shield the eyes from the sun’s glare.


How Polarized Sunglasses Work

The original polarized lenses had a film applied to them with millions of micrometer-sized polarized crystals that were in alignment with each other. Land was able to apply this film of crystals onto sunglass lenses. Those crystals could then redirect the light’s glare away from the eyes.

Without polarization, sunglasses simply darken your view of the world around you. That helps to reduce the bright sunlight and the glare from the sun. But it doesn’t redirect it.

If you have polarized sunglasses, they bounce some of the bright light off the lenses, which allows you to avoid glare even in lighter-shaded glasses, which can help you see more clearly. Imagine how the sun’s glare bounces off the surface of a smooth lake or sheet of metal. It does the same when it hits polarized sunglasses.
Land’s invention was such a success that his polarized film was used to make dark-adaptation and anti-glare goggles, target finders, sunglasses, cameras, and more for soldiers in World War II.

Today, you still have the option of purchasing polarized sunglasses, but you have to look for them. Not all sunglasses perform this function. Those available are much like those that Land made. They have a chemical applied to them that filters some of the light passing through them. The filter typically creates vertical openings for light, while blocking all horizontal waves.

This filtering effect does make the image a little darker, but objects look crisper and clearer and details are easier to see.

When You Should Wear Polarized Sunglasses

Do you need to wear polarized sunglasses all the time?

Not necessarily. They can help protect your eyes from glare and reduce eye fatigue whenever you’re out in the bright sunlight. So if you’re fishing, boating, golfing, or enjoying snow sports, polarized sunglasses are usually your best choice.

Polarized lenses are not recommended, however, if you’re focusing on your car dashboard controls, cell phone, or smartwatch. Then, they can actually make your vision worse. The American Academy of Ophthalmology (AAO) also suggests caution when purchasing polarized glasses that are supposed to help reduce glare when driving at night. Many of them may do more harm than good, making it more difficult to see road signs, obstacles, and ice on roads.

Finally, understand that polarized sunglasses are not the same as UV-blocking sunglasses. When you’re shopping, you’ll want to look for each of these labels. If you don’t see something saying “polarized,” the glasses will not block glare as well. Similarly, if you don’t see something about blocking UV rays, use caution.


Everyone Should Wear Sunglasses with Broad-Spectrum UV Protection

Scientists were concerned about UV exposure way back when sunglasses first came out. But it took the general public longer to understand just how important UV protection was.

UV light has shorter wavelengths than visible light, which means it contains more energy than regular light. As a result, it can more easily damage human cells in the skin and the eyes. You can see visible light, but you can’t see UV light, though some insects, like bees, can see them.

UV radiation is typically broken up into three categories:

1. UV-A: Makes up 95 percent of all UV rays that make it to the Earth’s surface. UVA penetrates deeply into the skin and eyes. It is most responsible for creating a tan and accelerating skin aging.

2. UV-B: About 95 percent of UV-B rays are absorbed by the Earth’s ozone layer. That means only about 5 percent gets through, but this is high-energy light. It doesn’t penetrate as deeply as UVA, but it can damage skin cells and cause DNA mutations as well as cataracts.

3. UV-C: The most harmful rays, but these are almost completely absorbed by the Earth’s atmosphere.


The National Institutes of Health (NIH) reports that UV exposure to the eye has been associated with cataract formation and retinal degeneration.

The AAO agrees, noting that too much exposure to UV light raises your risk of the following:

  • Cataracts
  • Age-related macular degeneration (AMD)
  • Eye cancers, including those on the eyelid
  • Growths on the eye
  • Sunburn to the eye

Today, the AAO recommends that you wear sunglasses that block UV radiation whenever you are exposed to the sun, which is whenever you go outside or when you drive your car or take another form of transportation where the sun comes through the windows.

That means that no matter what the season—warm or cold, sunny or cloudy—you need sunglasses to protect your eye health. UV rays are present on cloudy days too, so though you may not need your sunglasses to reduce the sun’s glare, it’s still best to wear them for protection.


1. 100% UV Protection

You want glasses that will shield you from both UVA and UVB rays. If the label says 100 percent UV protection, that’s similar to finding a sunscreen that offers “broad-spectrum” UV protection. Some labels will say, “UV absorption up to 400 nm” or “uv400.” That’s the same as 100 percent UV absorption.

If no label speaks to UV protection, assume the glasses do not have it and pass them by!

What if you have a pair of sunglasses but you’ve since removed the label? Is there a way to tell if they are adequately protecting your eyes?
You can take them to your optometrist and ask them to check them for you. Most offices have a photometer and will test your lenses for free.

2. Darker Lenses Aren’t Necessarily Better

You may think that sunglasses with darker lenses would better protect you from UV rays. They may, indeed, better protect you from the sun’s light and glare, but that doesn’t mean they are safer for your eyes. Always check for that UV-protection label.

The same is true for mirrored sunglasses. These may seem to offer more protection, and they do cut down on the amount of light entering your eyes, but again, it’s always best to check the label.


3. Polarization Doesn’t Mean Protection

Many manufacturers highlight the fact that their lenses are polarized. They are often targeting sports enthusiasts, as they understand that those who are active outside are often looking to reduce the glare from the sun.

Polarization, however, doesn’t offer protection from UV light. You must check for both.


4. Size Matters!

The size of your sunglasses matters when it comes to how well they can protect your eyes. When you’re outside, UV rays can enter your vision not only from straight ahead but also from up above, below, or beside your eyes.

If your eyes are at a higher risk for damage, consider wrap-around or oversized sunglasses for maximum protection. Otherwise, make sure your lenses give you a good area of protection around your eyes.


5. Choose Brown or Rose Coloured Lenses for Contrast

Aviator Sunglasses Fitted with Brown Tinted Sunlenses

If you have trouble seeing clearly with sunglasses, choose those with brown or rose-colored lenses. These can create more contrast in the objects you see, making them appear clearer. As long as the glasses are labeled as 100 percent UV-protective, the protection will be the same regardless of the various shades of lenses.


When Should You Replace Your Sunglasses?

Is it possible that, over time, sunglasses can lose some of their UV protection?
In a study out of Brazil, researchers claimed that under controlled and intense exposure to UV light, the UV protection in sunglasses gradually degraded. The scientists recommended additional research into the issue and suggested that people should replace their sunglasses every two years.

That recommendation assumes that you're wearing your glasses in direct sunlight for a minimum of two hours a day. Not many people do that, so it's unclear at this point what the suggestion should be.

We do know that in many cheaper sunglasses, UV protection comes from a coating applied to the top of the lenses. Over time, that coating can become scratched and worn, which can cause more UV radiation to hit your eyes.

Higher-quality sunglasses have UV protection baked into their scratch-resistant lenses and are made from more durable materials. These are likely to last longer and maintain their protection levels.


The most important thing when looking at sunglasses is to find those that will protect your eyes. Think of the sun’s rays as being equally damaging to your eyes as they can be to your skin, and wear your sunglasses every time you go outside or are exposed to the sun.

That shouldn’t be hard to do, as sunglasses look cool! We make limited edition sunglasses if you are interested join the waiting list now. Or if you are looking for some more helpful advice on which sunglasses may be best for you check out our other sunglasses blogs here.



Carlson, J. (2023, June 24). Survey says: Americans post high marks in sunglass awareness. INVISIONMAG.COM. https://invisionmag.com/survey-says-americans-post-high-marks-in-sunglass-awareness/

Effects of ultraviolet light on the eye: Role of protective glasses. (n.d.). PubMed Central (PMC). https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1568237/

Masili, M., Duarte, F. O., White, C. C., & Ventura, L. (2019). Degradation of sunglasses filters after long-term irradiation within solar simulator. Engineering Failure Analysis, 103, 505-516. https://doi.org/10.1016/j.engfailanal.2019.04.038

Share of people wearing sunglasses by season U.S. 2019. (2019, January 29). Statista. https://www.statista.com/statistics/1068781/adults-wearing-sunglasses-us-season/

What are polarized lenses for? (2022, June 15). American Academy of Ophthalmology. https://www.aao.org/eye-health/glasses-contacts/polarized-lenses

What's your risk of eye damage from UV light? (2021, June 11). American Academy of Ophthalmology. https://www.aao.org/eye-health/tips-prevention/eye-damage-from-uv-light