UV Protection and Sunglasses for Eye Health

The cornea, lens, and retina absorb UV radiation, and damage accumulates over a lifetime. By the time UV-related eye disease appears — typically in the 50s and 60s — decades of exposure have already contributed to it. Protection is most effective when started early and maintained consistently.

Types of UV radiation

UVA (315–400 nm) — penetrates deeper into the eye; associated with cataract and macular damage
UVB (280–315 nm) — absorbed primarily by the cornea and lens; associated with photokeratitis and cataract
UVC (100–280 nm) — almost entirely absorbed by the atmosphere; not a significant concern at ground level

Sunglasses rated UV400 block all light up to 400 nm, covering the full UVA and UVB spectrum.

UV-related eye conditions

Photokeratitis

A "sunburn" of the cornea from acute intense UV exposure — most commonly from reflected sunlight off snow or water. Symptoms (pain, tearing, light sensitivity) appear 6–12 hours after exposure and resolve within 24–48 hours. Prevention: UV-blocking eyewear during skiing, snowshoeing, or on open water.

Cataracts

The World Health Organization estimates that 20% of cataracts worldwide are attributable to UV exposure. The lens absorbs UV radiation and, over time, develops cloudiness (cataract) that reduces vision. UV protection throughout life reduces this risk.

Pterygium

A wedge-shaped growth of conjunctival tissue that can encroach on the cornea. Associated with UV exposure and prevalent in people who spend significant time outdoors. Surgical removal is required if it affects vision or causes persistent irritation.

Age-related macular degeneration

UV and high-energy visible light (blue light from sunlight, not screens) have been implicated as contributing factors in AMD development. Darker tints with blue-light blocking offer additional protection against bright sunlight exposure.

Choosing effective sunglasses

What matters

UV400 or 100% UV blocking label — non-negotiable
Lens size and frame coverage — larger lenses and wraparound frames block more UV from angles; smaller fashion frames leave the eye partially exposed
Lens quality — optical-quality lenses reduce distortion; important for driving

What does not determine UV protection

Lens darkness — tint level and UV protection are independent; a light tint with UV400 coating is more protective than a dark uncoated lens
Price — inexpensive sunglasses can offer full UV400 protection; expensive sunglasses without the UV label may not
Polarization — improves comfort and contrast but is separate from UV protection

Lens tints by activity

Grey — neutral colour rendition; good for general use and driving
Brown/amber — enhances contrast; good for variable conditions and sports
Yellow/orange — maximizes contrast in low light; useful for skiing or overcast conditions
Mirrored coatings — reduce glare and reflected light; useful in snow and water environments

Prescription sunglasses

If you wear glasses, prescription sunglasses provide full UV protection with your correct vision correction. Photochromic (transition) lenses darken in UV light but do not darken significantly behind car windshields (which block UV). Separate prescription sunglasses are the better option for driving.

Your optometrist can prescribe and fit prescription sunglasses at the same visit as your eye exam.

Frequently Asked Questions

Does UV radiation damage your eyes?

Yes. Cumulative UV exposure is a significant risk factor for cataracts, age-related macular degeneration, pterygium (a fleshy growth on the conjunctiva), photokeratitis (sunburn of the cornea), and eyelid skin cancers. UV damage is cumulative and irreversible, making early and consistent protection important.

What UV protection level should sunglasses have?

Sunglasses should block 99–100% of both UVA and UVB radiation. Look for labels stating 'UV400' (blocks all light up to 400 nanometres, covering the full UV spectrum) or 'blocks 100% UV.' The darkness of the lens tint is unrelated to UV protection — a clear lens can block 100% UV, and a dark lens without UV coating offers no protection.

Do polarized lenses protect against UV?

Polarization and UV protection are separate features. Polarized lenses reduce glare from reflected horizontal surfaces (water, snow, roads) which improves visual comfort and contrast — but polarization itself does not block UV. Most quality polarized sunglasses include UV400 protection, but check the label.

Are children's eyes more vulnerable to UV than adults?

Yes. Children's crystalline lenses are clearer than adults' and transmit more UV to the retina — estimates suggest children receive three times more annual UV exposure than adults per unit of outdoor time. Sunglasses and wide-brim hats for children are important, especially given they typically spend more time outdoors.

Do contact lenses protect against UV?

Some contact lenses (including certain daily and monthly soft lenses) include UV-absorbing material. However, contacts only cover the cornea — they do not protect the conjunctiva, eyelids, or surrounding skin. Sunglasses remain necessary even with UV-blocking contact lenses.

UV Protection and Sunglasses: What Your Eyes Actually Need