22 September 2021

Explained: Polarized vs Non-Polarized Sunglasses

The word "polarized" is something we've seen everywhere in the world of eyewear. Often, it means a pair of sunglasses is more expensive than its non-polarized counterpart. But what does "polarized" actually mean? And what are the benefits of having a pair of polarized vs non-polarized sunglasses?

Let's start with the basics: polarized eyewear has special lenses designed to reduce glare from reflective or bright surfaces. Polarized sunglasses are designed to filter out ambient light and counteract glare from reflective surfaces. Non-polarized lenses offer protection from light but do not have the filter built in to cancel out bright surface glare.

What are Polarized Sunglasses?

The lenses of polarized sunglasses are coated with a thin chemical film. This film eliminates much of the harsh, brilliant light that's reflected off water or highway surfaces on sunny days. Equipped with a pair of polarized sunglasses, wearers can see beneath the water's surface or through sunlit windows. Standard, non-polarized sunglasses, by contrast, reduce the intensity of bright or shimmering reflections.

How do Polarized Sunglasses Work?

Reflective surfaces such as flat water, glass, snow, or smooth hardtops polarize natural sunlight, concentrating waves in a single horizontal direction. This causes excessive dazzle, straining the eyes. The molecules coating polarized sunglasses are usually arranged vertically, like blinds on a window, blocking out the piercing slices of horizontal light. These molecular ''blinds'' let normal concentrations of the light pass but block out the intense concentrations of reflected light.

Polarized vs Non-Polarized

Non-polarized lenses treat all sunlight equally and reduce the overall intensity. This offers protection for the eyes but will not tackle shimmer and sparkle if you're around water, snow, or glass. Polarized sunglasses also filter ambient light but go further by cancelling out bright reflected light. This advanced performance can allow:

Anglers to see beneath the surface of a lake or river.

Boaters to ''read'' the texture of waves more clearly.

Drivers to focus unhindered on the road ahead.

Beach-goers to pick out the colours, contours, and contrasts of the sand and water better.

Both types of lenses make for more eye comfort on a sunny day, but polarized lenses actively counter the incapacitating effects of bright sunlight.

How to Tell if Lenses Are Polarized

Polarized and non-polarized lenses look the same, which is one of the reasons why you should always test sunglasses labelled as ''polarized.'' To do so, look through the lenses at a reflective surface then turn the lenses 90 degrees. If the lenses are genuinely polarized, the bright reflection will appear. 

Alternatively, hold the lenses in front of a backlit LED screen and rotate. This time, the screen will become darker for polarized lenses, whereas non-polarized lenses will reveal no change.

Points to Consider Outdoors

Many people notice the biggest difference between polarized and non-polarized sunglasses when they are outdoors.

The special coating in polarized lenses is highly anti-reflective, working around the clock to reduce reflections, haze and glare.

At the right angle, looking at a lake or ocean through polarized sunglasses will allow you to see past most surface reflections and through to the water below. Polarized lenses make them one of the best sunglasses for fishing and boating activities.

Their anti-glare properties are also great for scenic viewing and nature hikes all around; the coating increases contrast during the day and often makes the sky appear a deeper blue.

Polarized lenses' anti-glare and increased contrast traits also can help people who suffer from light sensitivity, although the benefit can vary depending on the strength or darkness of the lens.

Polarized lenses will tackle the discomfort caused by intense light sources; they perform the same as non-polarized lenses when it comes to filtering out harmful UV light. If your lifestyle regularly takes you outdoors, polarized and non-polarized sunglasses will give you essential UV protection. If you need the extra ability to see colours or contours accurately, however, polarized lenses will help.

Driving

Polarized sunglasses can be a lifesaver during sunny daytime driving, especially when sunlight hits at just the right angle to interfere with your vision. Polarized lenses filter the sunlight that reflects off roads, snow and windshields, neutralizing most or all of it. The result is a safer driving experience, free from the distraction and discomfort of glare.

It's more of a toss-up during brighter overcast weather since glare is less of an issue. Some people might feel like non-polarized sunglasses cooperate better with the lower contrast of total cloud cover.

It should be noted that driving with polarized sunglasses in certain snowy or icy conditions can be less safe than using a non-polarized alternative. Any patches of iced snow or black ice, which is already barely visible, may become even harder to see without surface reflections.

The same applies to skiing and other winter sports, where it's important to see slick patches in time to avoid them.

Screen usage

Bear in mind that polarized lenses don't perform as well as non-polarized when reading digital screens or displays, making them not as common among pilots. Likewise, polarized lenses make it harder to distinguish shiny patches of ice for those out walking, skiing, or driving after a snowfall, even if they reduce overall glare.

Digital screens, like those on your smartphone, laptop and TV, can sometimes look different when viewed through polarized lenses.

For example, screens viewed through polarized lenses can appear slightly faded or, in some cases, completely dark, depending on the angle from which you're viewing the screen. While this usually only happens when the screens are rotated at an unusual angle, it's worth noting that non-polarized sunglasses don't cause this visual distortion.

With that in mind, if you're experiencing symptoms of digital eye strain, talk to your eye care professional before getting polarized lenses. Instead of sunglasses, your eye doctor may suggest that you.

Wear computer glasses to block blue light and make screen time easier on your eyes.

Polarized lenses can significantly reduce eye strain, eliminate reflection, and improve performance in circumstances where the level of sunlight is overwhelming. However, if conditions are simply cloudy or overcast, a standard pair of non-polarized sunglasses should be sufficient to give your eyes that all-important UV protection.

Polarization, prescription and price

Both polarized and non-polarized sunglasses are available with a prescription and non-prescription lenses.

Polarized prescription lenses usually involve an additional charge on top of the included, basic lens option, but this isn't always the case. Some manufacturers include polarization as a standard feature or offer it free of charge. Make sure to read the fine print to find out if there might be an additional cost.

If you don't need prescription lenses, polarized sunglasses can cost the same or as little as a few dollars more than their non-polarized counterparts.

Are polarized sunglasses better than non-polarized shades?

Whether you choose to go the polarized sunglasses or non-polarized sunglasses route comes down to your preferences and how you plan to use your shades. Many people gravitate toward the perks of polarized sunglasses, while others prefer non-polarized sunglasses for a view that that's closer to that of the naked eye.

Of course, there there's nothing wrong with having one of each kind of sunglasses.

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