What are Polarized Sunglasses?

Last Updated on April 24, 2023 by amy

You might’ve seen the term “polarized sunglasses” thrown around a lot in recent years—that they’re beneficial for your eyes, they help your vision and a motley of other things. While it’s not untrue that polarized sunglasses can be helpful, what we mean by “helpful” can be very selective. And as concern regarding eye health grows, there is an increasing focus on how to better care for our eyes. Maybe you’re on that track of trying to see what will protect your eyes and polarized sunglasses is a pretty good starting point, especially if you plan on spending a lot of time outdoors. So we’ll take a look at what exactly it is that sets polarized sunglasses apart from all the other ones and how they can help you.

What is polarization?
We’re talking about “polarized” sunglasses, but what does polarized even really mean? What is polarization? After all, it sounds like a distantly obscure concept you haven’t thought about since high school physics. The concept is relatively simple. When the sun’s beautiful yet potentially harmful rays reach the Earth, they are vibrating or move in a manner of different directions and planes. This sort of unorganized reflection of light is essentially unpolarized light waves.

When the light waves from the sun hit a surface, such as asphalt, water, and snowfields, these unorganized light waves tend to be reflected parallel to the surface of these objects. Once this happens, the light waves are no longer reflected in a multitude of directions but in a singular plane and become what is considered “polarized”. Polarization is simply the process by which unpolarized light transforms into polarized light. Simple enough, right?

What are polarized sunglasses?
So we got polarization out of the way, but that still leaves us with what in the world polarized sunglasses do. We just discussed that polarization directs light waves such that they occur in a singular plane instead of in multiple directions. When we perceive light, we observe both vertical and horizontal waves. Now, vertical waves are helpful because they help us to see everything essentially. However, horizontal light causes glares that blind us while we’re driving or boating on a lake.

Sight good, glares bad. Since it’s the horizontal waves that hinder eyesight, polarized sunglasses have a special chemical film over the lenses, which filters out the horizontal oscillations while still allowing the vertical ones to get through. Think of polarized sunglasses as being like Venetian blinds—light can flow through, but only in the direction in which the blinds are pointed.

Regular sunglasses vs. Polarized sunglasses
At this point, or maybe even before this, you might have pondered the question, “What’s the difference between polarized sunglasses and regular sunglasses?” After all, you might say that both block out light and provide better vision in the sun. And this is true to a certain extent.

We mean that regular sunglasses without the “polarized” label will indeed block out sunlight. But these sunglasses indiscriminately block out both vertical and horizontal vibrations of light. This means that while glare is dampened, it is not eliminated. As we discussed earlier, vertical oscillations of light are essential to seeing everything, but since regular sunglasses work to block out even vertical waves of light, they can diminish the acuity of vision.

If polarized sunglasses are like Venetian blinds, regular sunglasses might be like a dark tinted film over the window—yes, they dim the brightness and some of the glare from the sun, but it doesn’t provide any clearer vision. So if you’re going for the looks, those $5 shades on the boardwalk might not be bad. But if you want better vision while driving or boating, polarized sunglasses are the better choice.

Protection with polarized sunglasses
The question that probably brought you here is, do polarized sunglasses protect your eyes? Very simply: yes and no. The answer to this question is mostly yes, but it depends on what’s meant by “protection.” For protection against UV rays, most, if not all, polarized sunglasses will usually come with a coating that blocks out 99-100% UV rays. However, you do have to double-check with the manufacturer or the label right on the polarized sunglasses to ensure that they block out UV rays. If there is no mention of protection against UV rays, then obviously, there is no protection with the sunglasses. If you want to be sure, you might run them by your optometrist to see if they offer legitimate protection.

The other aspect of protection critical to understand is the harm that might be done to the eye. Taking in too many UV rays obviously can cause damage to both the eye and other parts of the body, which is why it’s essential to take the initiative and wear protective eyewear. However, wearing polarized sunglasses does not imply they provide greater protection against UV radiation than regular sunglasses. After all, most regular sunglasses also offer 100% UV protection, just as polarized sunglasses do.

But polarized sunglasses offer a different form of protection in the sense that they provide greater clarity of vision when it comes to something like blocking out glares. Of course, even if there is no monumental difference in protection between regular sunglasses and polarized sunglasses, wearing either will afford greater protection as opposed to not wearing anything.

Do you need to get polarized sunglasses?
All polarized sunglasses provide protection for your eyes. However, that leaves us with the question of whether or not you need them. After all, regular and polarized sunglasses are the same regarding UV protection.

The need for polarized sunglasses depends on how and what you would use them for. And you must get the most use out of polarized sunglasses if you do decide to get them because they can be more expensive than regular sunglasses. Many boaters or anglers get polarized sunglasses because they help them see while on the water. This is because when the sunlight reflects off the water, the polarized rays are primarily horizontal, which, as we discussed, are the glares that you might’ve experienced before. For boaters and anglers, glares are a huge hindrance, especially when catching fish. But polarized sunglasses make them more effective in their work as they can see colors and objects more clearly.

As we all know, glares don’t occur just on the water. Even if you’re not a boater or an angler, polarized sunglasses might be helpful even daily, especially if you drive frequently.

Despite their practicality in shutting out glare, polarized sunglasses have disadvantages: there are certain situations when polarized sunglasses can be cataclysmic and dangerous. For instance, if you often go skiing or snowboarding, polarized sunglasses may not be for you—at least not on the mountain. At times there will be icy patches on the mountain slopes, and it’s important to be able to see these icy patches. But polarized sunglasses make it difficult to see the sun’s reflections on these ice patches and can delay your ability to react and avoid them.

The other circumstance in which polarized sunglasses may do more harm than good would be in scenarios where you may need to view LCD (liquid crystal display) screens or displays. Most modern motorbikes and aircraft have LCDs that may be crucial to the vehicle’s operation. And as polarized sunglasses make things more challenging to read or comprehend on these LCDs, they may not be a suitable choice if you are in a position dealing with a lot of such displays.

But remember that the only real difference between polarized sunglasses and regular sunglasses is the polarized filter and its ability to block out horizontal oscillations of light waves. In other words, they reduce glare. So you need to judge for yourself if you need that extra film.

Are all polarized sunglasses the same?
Maybe you got some polarized sunglasses and found a noticeable difference in the price range. Some cost under $50, while some surpass the $200 range. In terms of UV protection, they will probably be the same. The real difference exemplified/reflected in the price is the make and quality of the sunglasses themselves. This is about the quality of both the polarized film as well as the material of the glasses. The more economical polarized sunglasses will no doubt be less effective at reducing glares and less durable than the pricier ones—but this isn’t to say that they won’t do their job. The price difference also more specifically reflects how some polarized sunglasses will filter specific colors: one pair might make colors look flatter than another.

Just to recap, polarized sunglasses’ primary function is to block out glares. If you’re finding that you’re constantly dealing with glares on an everyday basis or protection for your eyes is a huge concern, consider getting a pair. But as with everything eye-related, consult an optometrist to see if polarized sunglasses are suitable for you.