Polarized sunglasses: what they do, and when they are worth it
Polarized lenses cut glare, not UV. What polarization does, when it helps, how to test a pair at home and why UV400 is the marking that matters.
The short answer
Polarized sunglasses filter reflected glare from flat surfaces; they are a filter, not a tint, and not a UV feature. UV protection comes from a UV400 marking, which both polarized and non-polarized lenses may or may not have. They matter most for driving, water and snow, and can make some screens and dashboards hard to read.
- Test with an LCD screen: a polarized lens makes it darken or go black at some angle.
Polarized sunglasses cut glare, and that is all they do. They do not block more UV light than other sunglasses, they are not darker, and they are not automatically better. Whether you should pay extra depends on where you spend your time: on water, on snow and on the road they make a clear difference, and in most other places they are a comfort feature, not a necessity.
What are polarized sunglasses?
Light reflecting off a flat surface such as water, a wet road or a car bonnet becomes polarized: its waves line up mostly in one plane, which is what you experience as glare. A polarized lens contains a filter that blocks that plane and lets the rest through. The result is less harsh reflection, richer colour and less squinting. Polarization is a filter, not a tint, and it can be added to any lens colour.
Are polarized sunglasses better than non-polarized?
They are better at one specific job, which is reducing reflected glare. For driving, fishing, sailing, skiing and sitting by water, that is a large comfort and visibility gain. For everyday walking in a city they matter much less, since there is little flat, shiny surface throwing light at you. As the American Academy of Ophthalmology explains in its guide to choosing sunglasses, the protection that counts for your eyes is UV blocking, and that is a separate feature.
| Polarized | Non-polarized | |
|---|---|---|
| What it does | Filters reflected glare from flat surfaces | Dims all light equally |
| UV protection | Only if the lens is marked UV400 | Only if the lens is marked UV400 |
| Best for | Driving, water, snow, long days outdoors | Everyday city wear, screens, low-cost spares |
| Screens and dashboards | Can look dim or patchy at some angles | No problem |
| Price | Usually costs more | Usually costs less |
Polarization and UV protection are independent: check for UV400 on every pair, polarized or not.
Do polarized sunglasses protect from UV?
Not by themselves. Polarization has nothing to do with ultraviolet light. A polarized lens can block 100% of UV or none of it, depending on the coating, and the marking to look for is UV400. We cover why a dark lens without that protection is worse than none in UV400 sunglasses: how to buy a pair. Check for UV400 first, and treat polarization as the extra.
When are polarized sunglasses not a good idea?
Polarized lenses can make some LCD screens hard or impossible to read at certain angles, including some car dashboards, phone displays and cash machines, because many screens emit polarized light themselves. Skiers and snowboarders sometimes avoid them because they can hide the sheen that marks ice on a slope. Pilots are often advised against them for the screen reason. If any of that applies to you, try a pair on with the screens you use before you buy.
How can you tell if sunglasses are really polarized?
- Look at an LCD screen through the lens and rotate the glasses. A polarized lens makes the screen darken or go black at some angle.
- Look at a reflection off water or a glossy floor, then tilt your head. The glare should drop noticeably through a polarized lens.
- Do not trust a sticker alone. A tag saying “polarized” is a claim, and the screen test takes ten seconds.
Which lens colour should you choose with polarization?
Polarization works with any tint, so choose the colour for how it changes contrast and colour accuracy. Gray keeps colours true and suits general wear and driving. Brown or amber raises contrast in variable light. Green sits between the two. Our table in the sunglasses buying guide sets out which tint suits what.
Are cheap polarized sunglasses worth it?
Often yes, provided they are marked UV400 and the polarization passes the screen test. Price buys optical clarity, frame durability and nicer hinges, not extra protection. A low-cost polarized pair is a reasonable spare for the car or the beach. Dima Eyewear is one brand that offers polarized lenses as an option on its sunglasses, at a lower price than the polarized pair from many fashion labels; the brand lists standard and polarized versions of the same frames, so you can compare the two. Dima Eyewear is a SOUL partner, and we earn a commission if you buy through our link.
Whichever pair you buy, check how the frame fits your face. The rule that makes shapes work is in our guide to glasses for your face shape.
Read next: Aviator Sunglasses: Face Shape, Size and Fit Guide
Questions people ask about this
What are polarized sunglasses?
Sunglasses with a filter that blocks the glare reflected from flat surfaces such as water, wet roads and car bonnets. It is a filter, not a tint, and it can be added to any lens colour.
Are polarized sunglasses worth it?
For driving, water, snow and long days outdoors, yes. For everyday city wear the benefit is smaller. They do not add UV protection, so check for UV400 either way.
Do polarized sunglasses block UV?
Not by themselves. Polarization and UV protection are separate. A polarized lens only blocks UV if it is marked UV400.
Why can't I see my phone through polarized sunglasses?
Many screens emit polarized light, so a polarized lens can dim or blank them at some angles. Tilting your head or the phone changes it.
How can I test whether sunglasses are polarized?
Look at an LCD screen through the lens and rotate the glasses; the screen should darken or go black at some angle. You can also check whether glare off water or a glossy floor drops noticeably.
