Everyone knows the importance of protecting the skin from too much sun, and we’ve all been warned of the possibility of skin cancer if we neglect to use sunscreen or long-sleeved shirts, or get sunburned too often. However, we don’t often think about the effect of the sun on our eyes, except to pick out a cheap pair of sunglasses or maybe a wide-brimmed hat before we go to the beach. Most people get annoyed by the glare of bright sunlight, but aren’t aware of the more significant eye problems that can come from too much exposure to sunlight – or more specifically, to UV radiation.

UV (or “ultraviolet”) radiation isn’t something that you can see or feel, but its effects can cause lasting health problems. Overexposure to UV radiation, whether it’s a natural part of sunlight or from an artificial source like a tanning bed, can lead to skin cancer, and that might mean the skin of your face or eyelids, which would put your eyes at risk. In addition, the UV energy has been shown to lead to early development of certain types of cataracts (a discoloration of the lens of the eye that blocks vision). UV radiation can also damage other parts of the eye, like the cornea.

To protect your eyes against UV rays, it’s important to choose the right pair of sunglasses. Keep these three tips in mind when you’re shopping:

Get the right kind of protection. Of the three types of ultraviolet radiation, the “A” type is what causes the most problems because it’s not blocked at all by the Earth’s atmosphere. The “B” type is partially blocked, and the “C” type completely blocked. Look for information on your sunglasses to confirm that they block 100% of the UVA and UVB radiation.

Know the vocabulary. You’ll see “polarizing” sunglasses or ones with mirrored lenses on the racks, but while they might be advertised as protective, unless they’ve been coated with a UVA/UVB coating, they’ll only help cut down on glare and visible light. It is important to reduce glare, which can lead to eye fatigue, but it’s also crucial to keep the long-term effects of UV radiation to a minimum.

Choose practical over pretty (unless you can get both). Shopping for sunglasses is the wrong time to think fashion. You need to make sure that you pick a pair of glasses with larger lenses to protect more of your eyes, and the wraparound style of glasses is an even better choice. Even if your preferred style of reading glasses is the minimalist frame-free rectangle, do your eyes a favor and buy the largest protective pair you can find.