Oct 12, 2026Frame Materials
Polarized vs UV400: A Buyer's Guide to Sunglass Lenses
Polarized and UV400 solve different problems. What each lens type actually does, what to stock for which customer, and how to check quality before ordering.
Every sunglasses buyer meets the two words 'polarized' and 'UV400' - and many product pages use them as if they meant the same thing. They do not. Understanding the difference helps you stock the right lenses for the right customer, and ask the right questions before you order.
UV400: protection first
UV400 means the lens blocks light up to 400 nanometres - effectively all UVA and UVB radiation. This is a health feature, not a comfort feature, and it is the baseline for any sunglasses programme in the EU under CE and in the US under FDA requirements. A dark lens without proper UV filtering is worse than no sunglasses at all, because dark lenses make the pupil dilate and let in more unfiltered light.
Polarized: comfort and clarity
Polarized lenses contain a filter that cuts reflected glare - the light bouncing off water, roads, snow and car bonnets. The result is clearer contrast and less eye fatigue for driving, fishing, skiing and beach use. What polarization does not do is block UV by itself: polarization and UV filtering are independent features, which is why a quality polarized lens is also UV400.
What to stock for which customer
Fashion and city retail: UV400 fashion tints and gradients - style leads, polarization is optional.
Driving, fishing and outdoor channels: polarized UV400 - glare cutting is the selling point customers will pay for.
Kids programmes: UV400 with impact-resistant lenses - protection and durability come before everything else.
How to check lens quality before ordering
Ask the factory for samples and test them yourself: a UV meter shows the actual blocking level in seconds, an polarization test card reveals whether the filter is real, and a simple rotate test against a screen shows how the polarization behaves. Check lenses at an angle for optical distortion - straight lines should stay straight.
Lens options at Fosoda
Fosoda produces polarized, UV400, gradient and solid colour lenses across more than 150 frame designs, with certified testing on every sunglasses programme. Tell us your market and price band, and we will recommend the lens specification that fits: sales2@fosoda.com or WhatsApp +86 137 9927 2707.
