Glaucoma is a disease that damages your eye's optic nerve. It usually happens when fluid builds up in the front part of your eyes. That extra fluid increases the pressure in your eye, damaging the optic nerve.
It is estimated that three million Americans have glaucoma, but only about half of them know that they have glaucoma. Glaucoma is a leading cause of blindness for people over 60 years old. But blindness from glaucoma can often be prevented with early treatment. When glaucoma develops, usually you don’t have any early symptoms and the disease progresses slowly. In this way, glaucoma can steal your sight very gradually. Fortunately, early detection and treatment (with glaucoma eye drops, glaucoma surgery or both) can help preserve your vision.
The optic nerve is connected to the retina a layer of light-sensitive tissue lining the inside of the eye and is made up of many nerve fibers, like an electric cable is made up of many wires. The optic nerve sends signals from your retina to your brain, where these signals are interpreted as the images you see.
In the healthy eye, a clear fluid called aqueous humor circulates inside the front portion of your eye. To maintain a constant healthy eye pressure, your eye frequently produces a small amount of aqueous humor while an equal amount of this fluid flows out of your eye. If you have glaucoma, the aqueous humor does not flow out of the eye properly. Fluid pressure in the eye builds up and, over time, causes damage to the optic nerve fibers.