The same UVB rays that cause sunburn (and cancer) on your skin can also burn your eyeballs. Eye-burn, called photokeratitis, or “snow blindness,” is painful inflammation or cell damage in the cornea. It’s reversible, but more importantly, it’s preventable—with sunglasses (and not staring directly into the sun or its reflection). Get yourself a pair of quality shades with lenses that absorb UVA, B and C rays.

MORE: How to Protect Your Eyes in the Sun