(WYTV) – Glaucoma is one of the world’s leading causes of blindness. Half of those with glaucoma don’t even know they have it, but you can protect your vision.

Driving down the road this is what you see when your eyes are healthy. A glaucoma can cause a loss of side vision, which can lead to tunnel vision and even blindness. Sometimes there are no symptoms at all until it’s too late.

“Unfortunately, it’s termed the silent thief of sight. And that’s primarily because most patients when they present aren’t aware that they’re even having it or in the advanced stages of it,” said Dr. Dave Patel, in ophthalmology at the Mayo Clinic.

Glaucoma is often caused when pressure builds up in your eye damaging the optic nerve.

The treatments including medications, laser procedures and surgery. The key is lowering that pressure. If you’re over 60 or have a family history of glaucoma, your risk is higher.

Your best defense is a regular comprehensive eye exam and that’s the way you want to protect your eyesight.