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What Are Polarized Lenses?

Polarized sunglasses.
Looking through polarized lenses through a prolonged period of time may cause headaches.
Polarized sunglasses are designed to reduce glare from light that is reflected off of surfaces like water or snow.
Most polarized lenses are laminated with tiny vertical stripes that only allow vertically angled light to enter the wearer's eyes.
To enhance contrast, photographers use polarizing lenses that screw onto camera lenses.
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  • Originally Written By: Michael Pollick
  • Revised By: John Allen
  • Edited By: L. S. Wynn
  • Last Modified Date: 21 September 2014
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Polarized lenses are transparent pieces of material, usually glass or plastic, that block certain types of light waves. Sunglasses and camera lenses are often polarized to reduce glare from surfaces, such as light reflecting off a lake or the hood of a car. Somewhat like the way Venetian blinds control the amount of sunlight passing through a window, polarization blocks as much as 50% of the light passing through a lens. The person looking through the lens can still see clearly in most cases, but it reduces the brightness and glare of light.

How They Work

When light bounces off of a surface, its waves tend to be strongest in a particular direction — usually horizontally, vertically, or diagonally. This is called polarization. Sunlight bouncing off a surface like water, a road, or metal will usually reflect horizontally, striking the viewer's eyes intensely and creating glare. Most polarized lenses in glasses are laminated with tiny vertical stripes that only allow vertically angled light to enter the wearer's eyes. Glare is eliminated because the horizontal light waves cannot bypass the vertical filter.

Lenses can be polarized to different degrees and in different ways. Most inexpensive polarized sunglasses have a thin film applied on one side of the lens. Many higher quality lenses have film laminated between two layers of lens material, preventing it from being scratched or rubbed off. In addition, the more dense the film is, the more polarization it provides.

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In most cases, polarized sunglasses don't look any different from regular sunglasses. While denser films tend to be darker, the color of a lens does not determine how much polarization it provides. A very dark pair of sunglasses with a light film will not block more glare than a lighter shade of glasses with a denser film. The color of the lens is also variable; although they cannot be made clear, polarized lenses can be made in gray, brown, green, or other colors.

Uses

Drivers, fisherman, and photographers were some of the first to use polarized lenses. Reducing glare can ease the eye strain drivers feel from long hours on the road. Fishermen can often see under the surface of water using the lenses, which helps them to see fish or other objects. Photographers use polarizing filters on camera lenses to enrich the images they capture by giving them more contrast, and to increase the range of effects they can produce.

Using horizontally and vertically polarized lenses together makes one type of three-dimensional (3-D) movies possible. Two images are projected onto a 3-D movie screen: one is polarized vertically and one horizontally. The lenses of the glasses that moviegoers wear are also polarized, one vertically and the other horizontally, so the user sees one image in one eye, and the second, slightly different image in the other. The brain is able to combine both of these images in a way that produces a realistic sense of depth.

Limitations

Polarized glasses do not provide universal protection from glare. If the wearer tilts his or her head past 45° or so, more of the horizontal light can enter and cause bright spots. In addition, these lenses do not usually work with snow glare because snow tends to reflect light equally in all directions, rather than the mostly horizontal reflection off of liquid water. It is strongly recommended that downhill skiers in particular not wear polarized sunglasses; ice does reflect horizontally, and these glasses can make dangerous icy spots less visible.

Because the polarizing stripes reduce the amount of light entering the eye, these lenses should not be used at night or in other situations where clear lenses are required. It is not possible to make such lenses truly clear; even those with low levels of polarization have a slightly gray hue. Some people find that looking through the lenses for too long a period of time can cause headaches and eye strain.

Polarized lenses can cause distortions in the way wearers see liquid crystal displays (LCDs), rendering some cell phone screens, clocks, and other displays unreadable. The texture of laminated or heat-treated glass, like a windshield, can be made more prominent by looking at it through a polarized lens, making the glass difficult to see through. Pilots should not use polarized glasses because they can make flight instruments difficult to read and other objects in the sky — including other airplanes — less visible.

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anon924808
Post 33

I use polarized lenses when I want to see if a person I'm looking at is human or not.

anon337357
Post 32

I wanted to make sure my new prescription lenses were polarized since they didn't seem as effective as my non-prescription sunglasses. I looked up how to test them (by holding them in front of my iPad screen and tilting them).

When I test my regular sunglasses, the lenses go evenly dark when tilted. With my prescription lenses, I see splotches of darkness as if someone spray-painted a dark X across the lens and left the corners without a coating. I'm assuming this isn't normal! Is there any situation in which the polarization can appear this way without it being an improper job?

anon335306
Post 31

I have paid for a pair of prescription, progressive "sunglasses" with a light brown tint which are neither polarized nor do they have had an anti-reflective coating applied. I don't see as well

as with my old polarized pair. Can the new pair be polarized and have the anti-reflective coating applied after the fact or will I have to buy a whole new lens?

anon327739
Post 29

When I google about polarized sunglasses I only find information about reflective glare. But what I find most dangerous while driving is the direct sun glare at sunset. Do those polarized sunglasses reduce that direct glare?

anon292474
Post 26

I don't know about anyone else, but I just bought a pair of Ray-Ban polarized shades and they are simply awesome. I wear them daily and I haven't had any problems with them.

Never, ever go for cheap polarized sunglasses. I just threw away my cheap polarized glasses since I used to get watery eyes every time I wore them.Then I got my Ray-bans. Just go for the branded ones. The rest are just crap.

anon275848
Post 25

I just received new polarized raybans, and they gave me a headache after five minutes. I'm going to return them.

anon191846
Post 23

Not all polarized lenses are made alike. Some manufacturers may be applying a cheaper polarized film to keep overall costs down. I had a pair of regular eyeglasses with a scratch-resistant coating that did the same thing after a few months.

When I went to the optometrist to get a new pair, she told me that her preferred lens makers didn't use that kind of coating. It may be the same thing with polarized sunglasses. The more expensive ones use a different kind of coating that doesn't peel off as easily.

anon168207
Post 22

I have been wearing a pair or polarized glasses for my running. To my disappointment, the surface of the lens which is in front of the eyes started to peel off just after six months of wearing them. What do you think? Is it because of the sweat and perspiration. Is it so sensitive to sweat? Please give me a hint!

anon167475
Post 21

Is there such a thing as a polarized gradient rx lens?

anon140429
Post 20

i have a feeling most of you have no idea what polarized lenses are for and the effects it has on looking at LED monitors.

Moreover, there's no such thing as cheap or expensive polarization. That's a marketing thing that makes you feel justified in paying $100+ more for a pair of sunglasses when they'll function the same.

That's like saying Versace clothes keep you warmer than Gap clothes.

periwinkle
Post 19

I have polarized sunglasses from an eyeglasses store and Oh my God, there is a huge blind spot. Me and my dog almost got killed today. I can't wear them anymore. Too bad I'm out $180 (and that's with some of it covered).

anon93890
Post 18

I just bought a pair of polarized prescription sunglasses. when i wear them and look at my monitor i can black spots on the outer edge of the lenses. is this normal or is it cause of a cheap polarization?

anon92868
Post 17

I bought a pair of polarized sunglasses and then a pair that were not just to try them side by side in the sun. I noticed the polarized significantly reduced glare and did make colors more vivid and bold.

However, for everyday use, regular lenses are good enough. If you have the money to spend on polarized lens then Id say go for it, but it will cause distortion when viewing LCD displays and will causes a rainbow effect when looking at windows at times, mostly car windows.

Second, if the sun is not shinning bright it can give a cold feeling since there is no glare entering to your eyes.

Bottom line: if you have the money and don't mind the cons, then yes, they are worth it.

anon86042
Post 16

I got polarized prescription sunglasses, and the polarizing doesn't seem to be consistent across the width of the lens. For example, if I close my right eye and look at a patch of glare with my left, the glare is greatly attenuated in the center of the lens.

But if I turn my head slightly (about a vertical axis) so I'm seeing the same glare out of the corner of my eye, the glare is much brighter. Are the glasses faulty or is this common?

anon77995
Post 15

I'm not a prescription lens wearer, and wear glasses only to protect my eyes from the sun. But I had a pair of quality polarized sunglasses in the past, and I didn't see what the fuss what about because I still noticed glare. I'm sure they have their place, but I think they're mostly hype.

anon77042
Post 14

I also bought polarized lens and they give me a headache and i feel like I'm seasick all the time.

anon68197
Post 12

I just purchased prescription polarized lenses and when I hold them up to a computer screen or TV one of the lenses has dark spots near the outside of the lenses. Is this faulty? The eyeglass provider said this is normal?

anon66952
Post 11

It is common for patients to see an "oil slick" pattern on car windows, and on LCD displays. Car stereo's, cell phones, and Navigation systems typically have screens that are pre-polarized. So when you put polarized glasses on you will in some cases have a difficult time seeing those screens. It's totally normal and will occur with non-rx and rx sunglasses that are polarized.

anon52642
Post 10

I have just bought polarized goggles. But when I see my car stereo display screen or side window, i see some colored floating lines. What is that? Are my goggles faulty, or does it happen with all polarized goggles?

anon45217
Post 9

The coloured lines mentioned could also look like darkened spots in shapes of a Maltese cross. This is due to the heat tempered glass found in vehicles (and some building windows). You can read more on this effect by researching heat tempered glass. For the poster who has progressives which turn into sunglasses when they go outside, are you wearing photochromatic lenses (which have a variable tint depending on how much UV exposure the lenses are receiving.) The lenses are not polarised (and they never were) so you will still experience reflected glare. regards.

anon39675
Post 8

I just got polarized sunglasses today that are progressive prescription lenses. While driving home I could see colored lines on the side windows of the car. That seems strange, what that about? Does that sound like they were made correctly? Sherry

anon38083
Post 7

To anon35585 - I work for an optician as a technician and to me this sounds to me that the polarised lenses are off axis. take these back as they are probably faulty. the axis has to be horizontal along your axis line.

anon37065
Post 6

I have progressive eyeglasses with polarization so when I go out they become my sunglasses. This effect seems to have worn off. Can my lenses be repolarized?

anon35795
Post 5

no actually horizontally polarised light is filtered by vertical polarisation filters. a polarisation filter does not filter light in the same plane of orientation as itself. analogy- vertical fence slats and rope, whipping the rope in the vertical plane through the slats, no resistance, whip in the rope horizontally and its stopped by the fence. think about it...

anon35585
Post 4

i just bought polarized sunglasses but when i where them they kind of mess up my vision,its like i have had a dozen drinks, just wondering whats that all about???

anon21650
Post 3

Actually, horizontal polarized light waves are filtered by *horizontally* aligned "stripes", not vertical ones

knittingpro
Post 2

Interestingly, polarized lenses make it possible to see what is under the surface of a lake - if the sun is shining off of the lake, I can't see anything with regular sunglasses, but with polarized sunglasses, I can see the frogs and fish under the surface!

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