Lenses are half of every pair of sunglasses — yet they’re where buyers most often get confused or, worse, mis-specify an order. UV400, polarized, “Category 3,” TAC, mirror coating: this guide explains what each term actually means and exactly what to tell your factory.
Key takeaways
- UV400 = eye health — blocks 100% of UVA/UVB (light up to 400nm). Independent of lens darkness or color.
- Polarized = visual comfort — cuts glare from reflective surfaces. Not the same as UV protection.
- Lens categories 0–4 rate darkness. Category 3 is the standard for bright sun; Category 4 is too dark to drive.
- Common materials: polycarbonate (sport/impact), TAC (polarized), CR-39 (clarity/value), nylon (premium), glass (optics).
- When ordering, specify UV rating, polarization, category, material, coatings and color.
What is UV400 protection?
UV400 means the lens blocks all ultraviolet light with wavelengths up to 400 nanometers — which covers 100% of both UVA and UVB radiation. This is the highest standard of UV protection in everyday eyewear.
The critical point for buyers: UV protection has nothing to do with how dark a lens is. A clear lens can be UV400, and a very dark lens can offer poor UV protection. In fact, dark lenses without UV protection are worse than no sunglasses, because they dilate the pupil and let more UV in. Always confirm UV400 explicitly.
UV400 vs polarized: what’s the difference?
This is the single most common point of confusion in sunglasses — and a great thing to get right, because the two features solve different problems.
| Feature | What it does | Protects against | Required for safety? |
|---|---|---|---|
| UV400 | Blocks UV radiation up to 400nm | UVA/UVB eye damage | Yes — health essential |
| Polarized | Filters horizontal glare | Reflected glare (water, snow, roads) | No — comfort feature |
A lens can be UV400 only, polarized only, both, or neither. Polarization does not automatically include UV protection. Premium sunglasses are usually both. When you order, specify each separately.
Understanding sunglass lens categories (0–4)
Lens categories — defined under EN ISO 12312-1 — rate how much visible light a lens transmits. This determines suitability for different light conditions:
| Category | Light transmission | Best for | Driving? |
|---|---|---|---|
| 0 | 80–100% | Clear/fashion, indoor, overcast | Day & night |
| 1 | 43–80% | Low sunlight, cloudy | Day & night |
| 2 | 18–43% | Medium sunlight | Daytime |
| 3 | 8–18% | Bright sunlight (most common) | Daytime |
| 4 | 3–8% | Very intense sun, mountains, desert | Not for driving |
Category 3 is the standard for everyday sunglasses. Category 4 is reserved for extreme conditions and is not legal for driving in most markets — an important compliance detail when exporting.
Common sunglass lens materials
| Material | Strengths | Trade-offs | Typical use |
|---|---|---|---|
| CR-39 | Good optics, low cost | Heavier, less impact-resistant | Value & fashion |
| Polycarbonate | Impact-resistant, light, built-in UV | Softer surface (needs coating) | Sport, kids, safety |
| TAC | Thin, cost-effective, ideal for polarized film | Lower scratch resistance | Polarized lenses |
| Nylon (polyamide) | Excellent optics + impact resistance | Higher cost | Premium sport |
| Glass | Best optical clarity, scratch-resistant | Heavy, can shatter | Specialty/premium |
For sport and children’s sunglasses, polycarbonate is the safe default. For polarized lines at accessible prices, TAC is the workhorse.
Lens treatments and coatings
Coatings let you differentiate a product and add value:
- Mirror (revo) coating — reflective finish; reduces glare and adds a fashion look.
- Gradient tint — darker top, lighter bottom; popular in fashion eyewear.
- Anti-reflective (AR) — reduces internal reflections on the back surface.
- Hydrophobic / oleophobic — repels water and fingerprints.
- Scratch-resistant hard coat — essential on softer materials like polycarbonate and TAC.
How to choose lenses for your eyewear brand
Work from your market and price tier:
- Always include UV400 — it’s expected and inexpensive; never sell sunglasses without it.
- Add polarization for outdoor/sport/premium lines — it commands a higher price and reduces glare.
- Default to Category 3 for general sunglasses; Category 2 for fashion/driving; Category 4 only for extreme-sun niches.
- Match material to use — polycarbonate for sport/kids, TAC for value polarized, nylon for premium.
- Use coatings to upsell — mirror and gradient finishes add perceived value at low cost.
See our sunglasses manufacturing page for the styles and options we produce.
What to specify when ordering
To get an accurate quote and the right product, tell your factory:
- UV rating (e.g. UV400)
- Polarized or non-polarized
- Lens category (0–4)
- Lens material (polycarbonate, TAC, CR-39, nylon, glass)
- Lens color and coating (solid/gradient/mirror)
- Target standard/market (e.g. CE / EN ISO 12312-1 for the EU)
Getting these six points right upfront avoids re-sampling and ensures your sunglasses pass import compliance. For more on that, read how to import eyewear from China.
Get a sunglasses quote
Tell us your lens specs, target market and quantity, and we’ll quote UV400, polarized and categorized lenses to match — with compliance documentation. Contact our team for a tailored proposal within 24 hours.