Sunglasses and UV protection

Why UV matters for eyes

Ultraviolet light from the sun can damage the eye’s surface, cornea and lens. Over years, unprotected exposure is linked to cataract, growths on the eye such as pterygium, and cancers of the eyelid. Intense short exposure, for example on snow or water, can cause photokeratitis, a painful sunburn of the cornea.

What to look for

100% UVA and UVB protection, or UV400. The American Academy of Ophthalmology says both labels mean the same thing.
Coverage. Larger lenses and wraparound styles block light from the sides.
Good optics. Look through the lenses at a straight line, such as a door frame, and move them; the line should not wobble.

Myths

Myth	Fact
Darker lenses protect more	Darkness does not show UV protection. Dark lenses without UV filters can let more UV in by widening the pupil
Polarized means UV-safe	Polarization cuts glare from water and roads; check the UV label separately
Only sunny days matter	UV gets through clouds and haze
Contacts with UV filter are enough	They do not cover the whole eye and lids; wear sunglasses too

Children

Children’s lenses let more UV reach the retina, and they spend a lot of time outdoors. Choose impact-resistant polycarbonate sunglasses with UV400 and a brimmed hat.

Solar eclipses

Ordinary sunglasses do not protect you when looking at the sun. Use certified eclipse glasses or viewers that meet the ISO 12312-2 standard, or watch indirectly with a pinhole projector. Looking at the sun can burn the retina permanently.

Questions people ask

Are expensive sunglasses better?

Not for protection. A cheap pair labeled 100 percent UV-blocking or UV400 protects as well as an expensive one. Price buys style, optics and durability.

Do I need sunglasses in winter?

Yes. UV passes through clouds, and snow reflects a lot of it. Skiers and snowboarders need good sunglasses or goggles.