The Complete Guide to Sunglass Lenses
UV protection, tint, darkness categories, polarization, and adaptive lenses — everything the lens does, and how to choose the right one.
The Two Jobs of a Lens
A sunglass lens does two separate things, and it helps to keep them apart. It protects your eyes from ultraviolet light, and it manages the visible light that reaches them, which is comfort, glare, and contrast. Protection comes from a UV filter you cannot see; everything else comes from the tint, the category, and treatments like polarization.
Confusing the two is the classic mistake: assuming a dark lens is a protective one. It is not. Learn the handful of specs below and you can read any lens correctly.
Blocks light up to 400 nm, covering essentially all UVA and UVB.
How much visible light a lens blocks, separate from UV.
A separate treatment that cuts reflected glare off flat surfaces.
UV Protection: The One Spec
Before color or darkness, a lens has to protect your eyes from UV. Look for one label: UV400, or a recognized standard mark such as CE or ANSI. It blocks light up to 400 nanometers, covering essentially all UVA and UVB.
Darkness does not equal protection. A dark lens with no UV filter is worse than bare eyes, because the tint opens your pupils and lets more UV in. Always confirm UV400, whatever the tint.
Buy the rating, not the tint. Full detail in what UV400 means, do cheap sunglasses protect your eyes, dark lenses without UV, and UV standards explained.
Tint and Color
Tint changes contrast, color, and comfort. It does not change protection. Pick the color for where you will wear the pair, then confirm UV400 separately.
| Tint | Best for | What it does |
|---|---|---|
| Grey | Bright sun, everyday | Keeps colors true, cuts brightness |
| Brown / Amber | Driving, variable light | Lifts contrast and depth |
| Green (G-15) | All-round, outdoors | Balanced contrast, easy on the eyes |
| Rose / Copper | Golf, cycling, sport | Sharpens green-and-brown contrast |
| Yellow | Fog, dusk, low light | Boosts contrast when light is flat |
Match a tint to your day with our Lens Color Guide, or read the best lens color for driving.
Darkness Categories
Lens darkness is graded 0 to 4 for how much visible light it blocks. This is separate from UV, and it decides where a lens is suitable, including whether it is legal to drive in.
| Category | Light blocked | Best for |
|---|---|---|
| 0 | Very little | Indoors, fashion, night |
| 1 | Light | Overcast, low sun |
| 2 | Medium | Moderate brightness |
| 3 | Dark | Bright sun, the everyday default |
| 4 | Very dark | High mountains, glaciers — not legal for driving |
Category 3 covers most bright days. Category 4 is too dark for driving, day or night. Full chart in sunglasses lens categories.
Polarized Lenses
Polarized lenses carry a filter that blocks the horizontal glare bouncing off flat surfaces: water, wet roads, snow, and car hoods. They cut that glare in a way a plain dark lens cannot. The trade-off is that they can dim some LCD screens and dashboards.
| Situation | Better choice |
|---|---|
| Driving, especially wet roads | Polarized |
| Fishing and boating | Polarized |
| Beach and snow glare | Polarized |
| Everyday city wear | Either, with UV400 |
| Pilots and heavy screen use | Non-polarized |
Polarization is not UV protection, so still confirm UV400. Full breakdown in polarized vs non-polarized, are polarized lenses worth it, and the screen trade-off.
Test a lens with the Polarized Checker ›Adaptive and Special Lenses
Photochromic
Darken outdoors and clear indoors, so one pair does both. They barely darken behind a car windshield. See photochromic explained and why they fail in cars.
Gradient
Darker at the top, clearer at the bottom, so they shade the sky while keeping a dashboard readable. See gradient lenses.
Mirrored
A reflective coating that cuts extra brightness in high glare, on top of any tint. See mirrored pros and cons and mirrored vs gradient.
We meter every pair we sell for UV, because the label is the claim that matters most and the one most often overstated. A lens can look dark, cost more, and still let UV through, so we verify rather than assume. Read our method on the About page.
Frequently Asked Questions
Does a darker lens protect my eyes more?
No. Darkness only affects glare and comfort. Protection comes from the UV400 rating. A dark lens without UV is worse than none, because the tint widens your pupils and lets in more UV.
What is the difference between UV protection and polarization?
UV protection blocks invisible ultraviolet light that harms your eyes. Polarization filters visible glare bouncing off flat surfaces. They are separate; a lens can have one without the other, so confirm both.
Which lens category should I choose?
Category 3 for most bright-day use. Category 2 for moderate light, category 1 for overcast. Category 4 is too dark for driving and made for high mountains only.
What is the most versatile lens color?
Grey or brown. Grey keeps colors true in bright sun; brown adds contrast and suits driving and changeable light. Both are safe everyday choices in a category 3 lens.
Are photochromic lenses good for driving?
Not on their own. Most photochromic lenses barely darken behind a windshield, which blocks the UV that triggers them. For driving, a dedicated tint, gradient, or polarized lens works better.
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Part of the Glasses Atlas Journal · Related: how to choose sunglasses · UV protection and your eyes · Last updated: August 5, 2026
