Lenses, not just frames
Is UV400 Enough, or Do You Need More?
UV400 already covers UVA and UVB. Extra numbers are often a blue-light marketing layer. Wrap and coverage still matter more than 420 versus 400.
Updated 27 Aug 2026 · 6 min read · is UV400 enough
400nm is the ultraviolet story
UVB 280–315nm, UVA 315–400nm. A UV400 lens is specified to block that band. ‘100% UV’ is the same claim in older copy. There is not a consumer UV500 problem you are failing by stopping at 400.
High-energy visible light (roughly 400–450nm) is visible violet-blue. Cutting it changes colour and can be a comfort choice. It is not a substitute for UV, and it is not required for a pavement Tuesday. See blue-light filters in sunglasses if that is the hangtag.
The gap is geometry, not nanometres
Light sneaks around a small flat lens. Wrap frames, larger lenses, and a closer fit cut that leak. A perfect UV400 stamp on a tiny fashion rectangle still leaves a strip of unprotected eye at the temple — the wrap problem.
| Claim | Do you need it |
|---|---|
| UV400 / 100% UV | Yes |
| Polarized | For glare, not for UV |
| UV420 / HEV cut | Optional colour/comfort, not extra UV |
| Category 3 tint | For brightness, not for UV |
| Wrap or large lens | Yes if you are in open sun for hours |
What to buy and stop reading
UV400, a frame that covers the eye, category 3 for bright sun. Polarize for water and road. Spend $20–$80 at a pharmacy if the meter passes; spend more for hinges and fit. Do not spend more for a 420 sticker.
Questions, answered
- Is UV400 the same as 100% UV protection?
- It is meant to be. UV400 is the clearer number. ‘Blocks UV’ without a cutoff is not a number.
- Do I need UV400 indoors?
- Not for typical indoor lighting. You need it outdoors, in a car, and near snow or water. Window UVA is real; a clear UV-blocking pair or photochromic covers errands.
- Are kids different?
- They need coverage and UV400, not a higher cutoff. Fit and not-losing-them matter more — see kids’ sunglasses.
