Glaucoma is a disease that damages the eye’s optic nerve. The optic nerve is connected to the retina — a layer of light-sensitive tissue lining the back of the eye — and is made up of many nerve fibers, like an electric cable is made up of many wires. It is the optic nerve that 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 continually 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.
Glaucoma can cause blindness if it is left untreated. Only about half of the estimated three million Americans who have glaucoma are even aware that they have the condition. 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 eyedrops, glaucoma surgery or both) can help preserve your vision.