Polarized lens at a glance
- Blocks
- Horizontal reflected glare
- UV protection
- None from polarization itself
- Best on
- Water, wet rock, snow, pavement
- Side effect
- Can darken phone and GPS screens
How does a polarized lens cut glare?
Light that bounces off a flat surface such as a lake, a wet slab or a snowfield comes back mostly vibrating horizontally. A polarized lens has a filter that lets through only vertically oriented light, so most of that reflected glare is stopped while the rest of the scene comes through.
On a trail that means you see into a creek instead of at its surface, and you see the texture of wet rock rather than a bright smear. Your eyes also work less hard over a long, bright day.
Do polarized sunglasses protect your eyes from UV?
Not by being polarized. The American Academy of Ophthalmology says polarization reduces glare but does not add protection from the sun. UV blocking comes from the lens material and coatings, so check for 100 percent UVA and UVB or UV400 on the label whether a pair is polarized or not.
When is a polarized lens a bad idea?
Two cases come up on a hike. Polarized lenses can make a phone, GPS or watch screen go dark when you tilt your head, because those screens emit polarized light of their own. And some climbers prefer unpolarized lenses on ice, since the glare a polarized lens removes is the sheen that tells you a patch is frozen.
What this means when you're choosing
- Polarized plus a stated 100 percent UVA and UVB or UV400 rating
- A check of your phone or GPS screen through the lens before a trip
- An unpolarized option if you cross glaciers or icy slopes
- A lens category that suits the light, since polarization says nothing about darkness
Polarized lens vs Unpolarized lens
| Polarized lens | Unpolarized lens | |
|---|---|---|
| Glare off water and wet rock | Strongly reduced | Comes through |
| UV protection | Depends on the lens, not the filter | Depends on the lens |
| Phone and GPS screens | Can go dark when tilted | Always readable |
| Spotting ice | Sheen is muted | Sheen stays visible |
Which to pick: Polarized is the better default for trails, lakes and coasts. Unpolarized suits glacier travel and anyone who navigates mostly by screen.
The common mistake
Treating polarized as a UV rating
Polarization and UV protection are separate features, and a cheap polarized lens with no UV filter protects your eyes less than a plain lens that blocks UV. Read the UV line on the label every time.
Common questions
Are polarized sunglasses better for hiking?
For most trails, yes. They cut the glare off water, wet rock and snow, which makes footing easier to read and tires your eyes less. They add no UV protection of their own, so the UV rating still has to be on the label.
Why does my phone screen go black with polarized sunglasses?
Phone, GPS and watch screens give off polarized light, and when the screen's orientation crosses the lens filter at right angles, almost none of it gets through. Turning the screen or your head usually brings it back.
Where this is defined
- How to choose the best sunglasses, American Academy of Ophthalmology