How to Know If Your Sunglasses Are Polarized

How can you know for certain whether or not your sunglasses are polarized, and why is it important to be sure?

Well, the truth is, there are unscrupulous eyewear manufacturers out there who claim their lenses are polarized when, in fact, they really are not! Polarized lenses are a very special type of sunglass lens – they don’t simply shade your eyes from the light, instead they filter light rays in a very specific way.

First, let’s look at what ‘polarizing’ actually means… which also means here comes the science…

Visible (for example the sun’s or a light bulb’s) light is effectively a wave… and as it travels towards your eyes it vibrates in all directions! When that light reflects off a surface, it bounces off chaotically.

A ‘polarized’ lens sometimes uses the application of a thin chemical film to only allow light vibrating in a certain direction through to your eyes. Higher quality lenses. Higher quality optics have a polarizing film laminated between two layers of lens material.

Most of the glare we encounter comes from horizontal surfaces – water, snow, a low-sunlit highway – so, the polarized lenses in sunglasses are fixed at an angle that only allows vertically polarized light to enter. When a polarizer is oriented vertically, it will block horizontal reflection.

Now you know what they are, how can you check?

There are a number of simple, and fun, ways to check whether the sunglasses you own, or are about to buy, really are polarized.

1 – Put the sunglasses on and look at a horizontal reflective surface (a car hood or a glass table, for example). When tilting your head slowly to the left or right, if your sunglasses are genuinely polarized, you’ll notice a brightening of the glare as you move your head from horizontal. BINGO!

2 – Tilt your head while looking at your computer or cellphone, and portions of your screen will become blank or go dark if you’re wearing polarized lenses! HOORAY! Why not try it now! The same is true of many LCD display screens – including those on a gas pump. Why does this work? Because most modern computer and mobile phone screens feature the same glare-reducing technology as polarized lenses. Clever stuff.

3 – On a new pair of sunglasses, you’ll often find a ‘test’ sticker. Hold the sunglasses you want to check at a 60-degree angle to it and, if your sunglasses are polarized, the sticker will appear darker! HURRAH!

4 – Take two pairs of polarized sunglasses and, holding them facing in the same direction, hold up to the light so one lens overlaps a lens of the second pair. Rotate one to a 60-degree angle and – hey presto – if it gets darker then BOTH pairs are polarized. If neither gets darker, one pair might still be polarized but, well, shucks and phooey to the other pair.

So, in a glare-free nutshell, there are numerous advantages to wearing polarized lenses, these include a reduction of eyestrain and improving vision by blocking excess glare. And, on a simple level, polarized sunglasses can even help reduce or eliminate headaches!

Polarized Sunglasses FAQ:

How can polarized sunglasses improve your vision? The reduction in glare offered by polarized sunglasses has many positive effects. It not only provides protection from exposure to bright light, it can also enhance visibility, contrast, clarity and depth perception.

Can I get polarized prescription sunglasses? Yes. The polarized process is created by applying a thin chemical film to a high-quality lens under laboratory conditions or through placing a polarized film between two layers of lens, and they are available in almost every prescription strength.

Are polarized lenses 100% UV protected? Not always. Polarizing and UV protection are two different things. A top-quality pair of sunglasses will always deliver a high-degree of UV protection, whereas a polarized lens’ main role is to reduce glare. However, in all cases, it is best to choose polarized lenses that also offer 100% UV protection.

Who is best suited to using polarized lenses? They are favored by outdoor enthusiasts, in particular skiers, climbers, cyclists, and fishermen. But polarized lenses make a great choice for anyone where the sun is strong and their environment includes many shiny surfaces – not only water, but the dazzling glass-facades of our city’s contemporary tall buildings too!