You might already regard sunglasses as a must for filtering out annoying, painful glare. But while this benefit is an important one, there’s another reason that sunglasses represent a critical form of eye care: UV protection. Radiation from the ultraviolet part of the spectrum can wreak havoc on your eyes in all sorts of ways. In addition to producing the uncomfortable “eye burn” known as photokeratitis, UV rays can put you at risk for cataracts, macular degeneration, and cancers of the eyes and eyelids. Don’t assume that a cloudy day means immunity from UV. In some cases, the reflections off of the clouds can make UV conditions even more intense than they would be on a sunny day. This ongoing threat makes the use of UV-blocking sunglasses a must.

Unfortunately, you can’t judge the degree of UV protection by the darkness of your sunglasses’ tint. Many cheaper sunglasses found in stores block a lot of visible light without blocking UV sufficiently to protect your health. The only kinds of sunglasses that truly offer the protection you need are “UV 400” sunglasses that are guaranteed to block the entire ultraviolet range.