Sunglasses get sold on two words — polarized and UV — and most people aren't sure what either one buys them. They're unrelated features that solve different problems, and only one of them protects your eyes.
UV400 is the part that matters for your eyes
UV400 means the lens blocks light up to 400 nanometres, which covers both UVA and UVB. That's the specification worth checking, and it's the one doing the actual protective work.
Here's the part people miss: tint darkness and UV protection are completely independent. A dark lens with no UV filter is worse for you than no sunglasses at all, because the darkness makes your pupils open wider and lets more unfiltered ultraviolet reach the back of your eye. Dark is comfort. UV400 is protection. Don't read one as evidence of the other.
What polarization actually does
When light bounces off a flat surface — water, wet asphalt, a car hood, snow — it comes back horizontally organised. That's glare. A polarized lens has a filter that blocks light on that one plane while letting the rest through.
The result isn't darker, it's cleaner. Reflections drop off a lake so you can see into it. Road shine flattens out. Contrast goes up and you stop squinting on bright days, which is where most driving headaches come from.
Where polarization gets in the way
- Screens. Phone displays, car dashboards, ATMs and aircraft instruments are often polarized themselves. Through polarized lenses they can dim, shift colour or black out at certain angles.
- Ice. Skiers and drivers in freezing conditions sometimes want the glare — that sheen is how you spot black ice.
- Some pilots and machine operators avoid them for exactly the instrument reason above.
For everything else — driving, water, beach, everyday sun — polarization is the single biggest comfort upgrade available in a lens.
Tints, and what each one is good at
- Grey. The neutral choice. Cuts brightness without shifting colour, so everything looks like it does to the naked eye, just dimmer. Best all-round pick and the safest for driving.
- Brown and amber. Warms the view and lifts contrast, especially against green and blue backgrounds. Good in variable light, good for depth perception, popular for driving and outdoors.
- Green. Between the two. Slight contrast boost, fairly natural colour, easy on the eyes over long stretches.
- Mirrored. A reflective coating on the outside that bounces more light away before it reaches the lens. Useful in very bright conditions — open water, snow, high altitude. Shows fingerprints readily.
- Gradient. Dark at the top, clear at the bottom. Shields overhead sun while leaving your dashboard or book readable.
Fit matters more than people expect
A frame that sits badly gets left at home no matter how good the lens is. Two things to check: the bridge should rest on your nose without pinching or sliding down, and the arms should hold at your temples without pressing. If the frame is wider than your face, it'll slip; narrower, and it leaves marks.
Coverage counts too. Light coming in from the sides and above is real exposure — wraparound or larger frames simply block more of it.
If you want to work out which shapes suit your face before choosing a tint, we wrote a separate guide: The Right Sunglasses for Your Face Shape.
Keeping them clear
Rinse before wiping. Dust is abrasive, and dry-rubbing grit across a lens is how coatings get scratched. Use a microfibre cloth, not a shirt hem. Skip household glass cleaners — the ammonia in them eats coatings. And store them in a case rather than face down on a table, which is where most lenses meet their end.
Every pair we carry is listed with its lens and frame details up front, so you know what you're getting rather than guessing from a product photo.
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