The Capo Journal · Lens Knowledge
Not everything that looks protective is.
There's a misconception worth clearing up first: dark lenses do not equal sun protection. A very dark lens with no UV treatment can do more harm than wearing nothing — the pupils dilate behind the darker lens, letting more radiation into the eye while giving the impression of safety. Lens colour and UV-filtering capability are two entirely separate things. Understanding that difference is the single most useful thing in this article.
What UV400 actually means
UV400 is the benchmark to look for. It means the lens blocks ultraviolet radiation up to 400 nanometres — covering the entire range of UVA and UVB rays that reach the earth's surface. A frame with this rating provides complete ultraviolet protection regardless of lens colour. This is the standard to require in any quality sunglasses. Not a bonus — a baseline.
UVA vs UVB: the difference
UVB
- Higher energy, the radiation behind sunburn
- Immediate, visible, felt the same day
- Strongest in summer, 10am–4pm
UVA
- More persistent, penetrates deeper into eye tissue
- No immediate sensation — present even through cloud and glass
- Damage is cumulative, built over years
Long-term UV exposure without proper eye protection has been associated with cataracts and other eye conditions. Quality sunglasses are not purely a style decision.
Polarised lenses
UV protection and polarisation are often confused. Polarised lenses filter out horizontal light reflected from flat surfaces — water, wet roads, sand, car bonnets — eliminating glare and improving clarity, especially when driving or near the sea. Polarisation complements UV protection but doesn't replace it. Both functions can coexist in a single lens.
“A dark lens isn't a protective lens. UV400 is.”
UV in cold and cloud
UV radiation doesn't stop when the sun isn't visible. Up to 80% of UV rays penetrate cloud cover. Snow reflects a significant amount back upward, creating double exposure. High altitude amplifies intensity further. Year-round eye protection matters — not just in summer, and not only in direct sun.
Di Capo and UV protection
Di Capo sunglasses from the Passaporto collection are designed with UV protection as a fundamental specification, not an optional feature. Check individual product pages for full lens specifications on each model. And if you're choosing a frame, our complete sunglasses guide covers shape, material and lens together.
Protection and character. Not a compromise.
Discover the Passaporto collectionFrequently asked
Does a darker lens mean more protection?
No. Lens darkness and UV protection are unrelated. A dark lens with no UV treatment can be worse than none, because the pupils dilate and let in more radiation.
What does UV400 mean?
It means the lens blocks ultraviolet radiation up to 400 nanometres — the full UVA and UVB range that reaches the earth's surface, regardless of lens colour.
Is polarisation the same as UV protection?
No. Polarisation reduces glare from flat surfaces; UV protection blocks radiation. They can coexist in one lens but are not the same thing.
Do I need sunglasses on cloudy days?
Yes. Up to 80% of UV passes through cloud, and UV exposure is year-round. Protection isn't only for bright summer days.
How can I check my current sunglasses' UV rating?
Any optician can test the lenses in under two minutes with a UV spectrometer. If they don't meet UV400, they aren't protecting your eyes.
Read more in The Capo Journal.