What is Glaucoma?
Glaucoma is an eye disease that causes loss of sight by damaging a part of the eye called the optic nerve. This nerve sends information from your eyes to your brain. When glaucoma damages your optic nerve, you begin to lose patches of vision, usually side vision (peripheral vision). Over time, glaucoma may also damage straight ahead (central) vision. You may not notice a loss of side vision until you have lost a great deal of your sight. When checking for glaucoma, eye doctors usually look for damage to the optic nerve and any loss of side vision. They may also check your eye pressure.
Glaucoma is often called "the sneak thief of sight." That’s because people usually do not notice any signs of the disease until they have already lost significant vision. Once lost, vision can't be restored. More than 2.7 million Americans age 40 and older have open angle glaucoma, the most common form of glaucoma. At least half don't even know they have it.