How Do Polarized Sunglasses Work?
If you’re thinking about buying a new pair of sunglasses, you’re already well aware of the many, many options you have.
No matter what your personal style is or what functional features you need, you couldn’t possibly begin to consider all the sunglasses out there.
Of course, we like to think we’ve made the decision easy, but not everyone likes affordable, durable sunglasses that also look great.
Nonetheless, even if you insist on buying ugly, overpriced shades that will break the first time you set them down wrong, we insist you at least make sure they're polarized sunglasses.
But, what are polarized sunglasses?
How Polarized Sunglasses Work
Before we talk about how polarized sunglasses work, we need to quickly cover how sunlight works. We promise to make it painless. We’ve even included a cute dog video.
It turns out that light emanating from a gigantic dying star that has been exploding for billions of years is actually quite erratic. Who knew? So, although we tend to think of light waves moving in straight lines, they’re actually vibrating all over the place.
Imagine them like the balls in this video featuring competitive wiffleball throwers (you’re learning all kinds of things today):
The ball is headed in one direction, but man does it move around before it gets there.
That’s like sunlight.
Now, what happens to that ball when the batter smacks it? No more wobbling around. Its movement is completely predictable in a very straight path.
When light reflects off a horizontal surface, it no longer wobbles around, either. It reflects as a concentrated beam of horizontal waves. We perceive this resulting horizontal motion as glare.
Credit where credit’s due, Étienne-Louis Malus discovered this phenomenon back in 1809 and, yes, I tried finding a picture of him wearing sunglasses.
In fairness, it was actually this dapper-looking fellow, Edwin Land, who finally said, almost 150 years later, “Hey, why don’t we take what that French guy was on about and use it to make sunglasses that actually do their job?” (I’m paraphrasing)
Alright, maybe not everybody
Land created his polarized lenses by covering them in a chemical laminate that is applied vertically. Any light trying to move through them horizontally gets the boot.
Let’s look at another very scientific video to illustrate this point.
Imagine Theo’s stick is sunlight moving in a horizontal path and the bridge is a polarized lens. As long as poor Theo keeps holding that stick horizontally, it’s not getting past.
So, polarized sunglasses don’t block out all light. That would…well, that would just be a blindfold. They let in a comfortable amount of direct sunlight while stiff-arming any that has been reflected into glare.
This is why the right sunglasses are especially important for people who like to spend their free time on or near the water. Lifeguards, fishermen, and golfers who wear normal sunglasses aren’t safe from direct exposure to the sun or from rays that bounce off the water nearby.
Water isn’t the sun’s only accomplice, though. Rays can reflect off of the road, snow, glass, and countless other surfaces. Sufficed to say, if you spend a lot of time in the sun, you should wear polarized shades. Even a wide-brimmed hat can’t protect you from the sun’s sneaky rays.
The Multiple Benefits of Polarized Sunglasses
In any case, there are three other reasons polarized sunglasses are an important staple in sunny weather.
Reducing Eye Strain
Even if you’re only outside for a couple of hours a day, you could develop eye strain, which happens after your eye muscles and nerves have been overtaxed. It’s common among fishermen, lifeguards, and anyone else who has to regularly deal with glare coming off the water. The same goes for people who spend long hours on the road every week. The glare coming off other people’s vehicles can push your eyeballs past their limit.
Your eyes after a long day of straining against glare:
Fortunately, polarized sunglasses will give your peepers the protection they need to deal with all this extra sunlight.
True Color Conveyance
That’s just a fancy way of saying that polarized sunglasses won’t distort the colors around you. If you wear nonpolarized sunglasses for long periods of time, you’ve probably experienced the shock of taking them off and realizing something was a completely different color than you had thought. Often, nonpolarized lenses skew colors towards yellow, pink, or red.
This isn’t the case with polarized shades. There’s no tradeoff between protection and seeing the world around you in its actual colors.
Maybe you already know all about the benefits of polarized lenses. As we covered earlier, this isn’t brand-new technology.
But maybe you’ve been putting off your purchase because you’ve come to expect that polarized sunglasses may save your eyes, but they won’t save you money.
To be fair, they have been expensive in the past. And, yes, many brands still insist on charging you an arm and a leg in exchange for your eyes.
But at least one brand we know of (hint, hint) has made them extremely affordable. So, you don’t need to choose between keeping your eyes safe from sunlight and keeping the lights on at home.
Polarized vs. Nonpolarized Sunglasses
By now, the difference between polarized and nonpolarized sunglasses should be clear. Like good bouncers, polarized lenses force sunlight to behave or stay outside.
Nonpolarized sunglasses lack this chemical fortitude. They treat all sunlight the same, including the kind that gets reflected and causes glare. For the most part, nonpolarized lenses are just color-treated plastic or glass – that’s it.
Polarized sunglasses vs. glare:
Nonpolarized sunglasses vs. glare:
How Do I Know if My Sunglasses Are Polarized?
If you already own polarized shades, it should be obvious when you wear them outside. If you don’t notice any glare coming off reflective surfaces or harsh light bouncing off the water or sidewalk, you’re probably wearing polarized sunglasses.
However, there are two other ways you can check to see if your lenses are polarized:
- If you already have one pair of polarized glasses, hold one of their lenses in front of one of the lenses from your pair in question. You should be able to see through them fine, but when you turn one 60 degrees, if the lenses go black, congrats. You have two pairs of polarized glasses.
- Put your sunglasses on and look at an LED or LCD screen. The screen should be dim, but if you tilt your head to the side and it goes black, you got yourself some polarized sunglasses.
A third option, which we do not recommend, is to just wear that pair outside in direct sunlight for years on end. If you develop cataracts or macular degeneration, then we have bad news (aside from the troubling diagnosis): those sunglasses were not polarized.
So, yeah, probably just look at your phone to test them.
Is It Ever Better to Wear Nonpolarized Sunglasses?
We’ll give nonpolarized lenses their due: if you regularly work with LCD and LED screens outside, they’re the superior choice. Some cyclists prefer them if they use GPS or speedometers. For the same reason, if you’re a pilot, do not wear polarized sunglasses. You definitely need to read all of those fancy instruments.
Skiers and snowboarders often opt for nonpolarized lenses, too. On really sunny days, glare may be the only thing that helps them distinguish between snow and ice. Telling the difference could mean the difference between life and death, so that’s kind of a big deal.
“But where oh where am I going to find polarized sunglasses?”
That is so weird you ask.
At Runners Athletics, we actually make polarized sunglasses that are affordable, functional, and fashionable.
If you want polarized shades that don’t cost a fortune, can stand up to normal wear-and-tear, and look really, really good, check out our sunglasses.