What Are Polarized Sunglasses, and Are They Really Worth the Cost?

A dog wearing sunglasses relaxes in a hammock.
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Sunglasses are one of those things you can spend $20 or $200 on — or even $200,000, if you want to. 

As a certified Penny Hoarder, I have two simple metrics for a killer pair of shades: They protect my eyeballs, and they don’t cost a fortune. (Bonus points for making me look cool, too.) 

I definitely don’t want to spend a big chunk of change on something I’m likely to lose, scratch or sit on. That said, I’m willing to put in the money for a pair that actually performs. 

Which begs the question: What exactly is polarization, which tends to cost extra? Is it worth the surcharge? What does it have to do with actual UV protection, which is the primary purpose of any pair of sunnies?

Polarized vs. Non-polarized Sunglasses

Let’s debunk one myth right from the get-go: Your sunglasses don’t have to be polarized to protect your eyes from UV rays. Rather, polarization is about reducing glare, which can help if you’re spending time near reflective surfaces like the ocean or a snowy ski slope… or a traffic jam filled with shiny cars. 

Polarization is actually a chemical process: A special film is applied to the lenses during manufacturing, and it reorganizes the way light comes through the glasses. We won’t get too technical on you, but the upshot is that certain light waves are filtered out, which leaves the wearer less glare to deal with.

Since they can help you see more clearly, reduce eye strain and improve color perception, polarized sunnies are often preferred to their non-polarized counterparts, particularly if you’re playing outdoor sports or driving.

But non-polarized shades can still protect your eyes from the sun, even if the world still feels a little bit too bright when you don them. And while most polarized shades do offer UV protection, it’s not a given: You have to look for both attributes when you’re shopping for your next pair.

How to Tell if Your Sunglasses Are Polarized

These days, most sunglasses offer full-spectrum protection against UVA and UVB rays — even the cheapies. You’ll likely find a sticker (annoyingly placed directly on one of the lenses) stating the UV protection rating while you’re shopping, but if you’re wondering about an existing pair, you can take them to an optical shop where they can test the lenses with a photometer.

In some cases, you might also find the answer in the string of numbers and letters printed on the inside of your glasses frames along the arm. 

The very last number you see, a standalone digit, will correspond to the lens category, which ranges from 0 (translucent, with no UV protection) to 4 (darkest tint). Categories 2 and above are fully UV protective, though the higher the number, the more comfortable you’re likely to find the tint in bright light.

To determine polarization, all you need is what you have in front of you right now: your computer or your phone. By holding your sunglasses in front of the screen and rotating them, you’ll be able to tell if they’re polarized by the way the coloration shifts. (This YouTube tutorial makes it super simple.)

Are Cheap Sunglasses Still Good?

A person shows the view through the lens of a pair of sunglasses.
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Now that we’ve sussed out the difference between polarized vs. non-polarized sunglasses and learned that polarization is a totally different thing from UV protection, let’s talk turkey. Is it worth it to shell out extra dough for a pair of polarized glasses?

The answer, as in darn near everything personal finance, is maybe. It’s up to you to decide whether glare reduction is worth your investment… though if you drive, it’s probably a good idea. In super bright conditions, the glare off other cars and mirrors can be downright blinding, which could lead to a dangerous situation on the road.

You definitely want to make sure that your sunglasses offer UV protection. But since all sunnies sold in the U.S. have to comply with the ANSI Z80.3-2001 safety standard, which specifically mentions UV transmission, it’s hard to find a pair that don’t meet that metric.

Either way, the good news is you don’t have to shell out $150-plus for a pair of fancy Ray Bans to ensure your peepers are protected. 

Direct-to-customer internet marketing has changed the way we buy sunglasses. For instance, you can find solid UV-protective pairs from San Diego-based vendor Knockaround starting at just $15, and it only costs $5 to add on the polarization option. 

Plus, they’re darn near indestructible… and when you’re as clumsy and cost-averse as I am, that’s just about the highest virtue a pair of sunglasses can attain.

Jamie Cattanach is a writer whose work has been featured at Fodor’s, Yahoo, SELF, The Motley Fool and other outlets. Her focuses include personal finance, travel, body image and more; she writes to find (and share!) the best ways to live intentionally, adventurously, and happily.