Why UV Protection in Sunglasses Matters
Ultraviolet radiation — specifically UVA and UVB — damages the eye's surface tissues and internal structures over time. Cumulative UV exposure is linked to cataracts, macular degeneration, pterygium, and photokeratitis (essentially a sunburn of the cornea).
UV400: The Standard to Look For
UV400 means the lens blocks 100% of UV radiation up to 400 nm — covering both UVA and UVB completely. This is the minimum standard recommended by eye care professionals worldwide. If a product does not mention UV400, treat it as decorative eyewear only.
The Dangerous Misconception: Dark Lenses = More Protection
This is false. Lens darkness (tint) reduces visible light transmission but has no direct relationship with UV protection. A very dark lens without UV400 coating can actually be worse than no sunglasses at all — the pupil dilates to compensate for the dark tint, allowing more UV radiation to reach the retina.
Polarised Lenses vs UV Protection
Polarisation reduces glare from reflected surfaces (water, roads, car bonnets) — it is a separate feature from UV protection. Look for both if you drive or spend significant time near water.
What to Check When Buying
- Look for "UV400" or "100% UV protection" on the tag or frame.
- For children, prioritise UV400 above style — UV exposure starts in childhood.
- Larger lenses that cover more of the eye area provide better peripheral protection.
- Wrap-around styles prevent UV from entering from the sides.