Glaucoma is a group of eye diseases that can lead to permanent vision loss. Inside your eye, there's a clear fluid called aqueous humor. It nourishes the tissues and keeps the eye's shape by providing pressure, similar to the air in a balloon.
In most types of glaucoma, the eye's natural drainage system doesn't work properly. This causes the fluid inside the eye not to drain. This leads to increased pressure inside the eye, which can harm the optic nerve and cause vision loss.
Most forms of glaucoma don't show any symptoms until the vision loss becomes severe enough to impact a person's quality of life. An estimated 2.5 million Americans have glaucoma, and half of them don't know they have it. About 130,000 Americans are currently blind because of glaucoma, making it the second most common cause of blindness worldwide. There are several important risk factors for glaucoma, including high eye pressure, family history, race and age.