Why wear sunglasses?

Ultraviolet (UV) light can damage your eyes. Wearing the right kind of sunglasses outdoors may reduce your risk of eye damage from ultraviolet light. UV rays are as strong on cloudy days as on sunny days.

What eye problems are related to UV light?

UV light from the sun increases your risk for:

• Cataracts. A cataract is a cloudy area in the lens of the eye. The lens is located inside the eye behind the colored part of the eye. For some people, the lens gets cloudier over time and causes vision problems.
• Age-related macular degeneration (AMD). AMD is a disease that damages the macula in the eye. The macula is in the center of the retina. The retina is the lining at the back of the eye that senses light coming into the eye. The macula allows you to see fine details in the center of your field of vision. AMD can make it hard to read, drive, or recognize faces.
• Pterygium or pingueculum. These are growths on the clear membrane that lines the inside of your eyelid and covers the white part of your eye. These growths are common in people who spend a lot of time outdoors in sunny climates.
• Skin cancer. The eyelids are a common place for skin cancers.
• Sunburn of the cornea (the clear outer layer on the front of the eye). This may also be called snow blindness.

What kinds of sunglasses are best?

UV protection is not related to how dark the lens is. Look for sunglasses that protect you from 100% of both UVA and UVB light. This includes those labeled as “UV 400”. If the label says only “blocks most UV rays”, the glasses will not protect your eyes.

If you are outdoors a lot, you may want to wear wrap-around glasses, which also protect your eyes from the sides.

Polarized lenses reduce glare reflected from surfaces such as water or snow. However, they don’t block UV light unless they are combined with a coating that blocks UV. Mirror coatings alone do not provide UV protection and should be combined with a UV-blocking coating.

Photochromic lenses are almost clear in low light and turn dark in bright light. They react to UV light and not to visible light. A car windshield blocks out most UV light, which means that photochromic lenses will not darken in the car. Ask your eye care provider about tint options.

Lens color does not affect how well sunglasses protect your eyes. Gray and brown are least likely to distort the colors you see. Skiers may choose yellow lenses to help reduce haze in low light.

Who should wear sunglasses?

Wide-brimmed hats may keep about 50% of UV rays from reaching the eyes, but you should also wear sunglasses. Sunglasses are very important if you:

• Work outdoors, such as farmers and construction workers
• Already have eye problems
• Take certain medicines, such as tetracycline, allopurinol, phenothiazine, and psoralen
• Are outdoors at high altitude or near the equator
• Spend a lot of time on snow or water