Glaucoma is a group of eye conditions that damage the optic nerve, which is vital to good vision. This damage is often caused by an abnormally high pressure in your eye.
Glaucoma is one of the leading causes of blindness in the United States. It can occur at any age but is more common in older adults.
The most common form of glaucoma has no warning signs. The effect is so gradual that you may not notice a change in vision until the condition is at an advanced stage.
Vision loss due to glaucoma can't be recovered. So it's important to have regular eye exams that include measurements of your eye pressure. If glaucoma is recognized early, vision loss can be slowed or prevented. If you have the condition, you'll generally need treatment for the rest of your life.
Learn about the symptoms, causes and risk factors of glaucoma.
Normally, fluid (aqueous humor) flows freely through the anterior chamber by way of a drainage system (trabecular meshwork). If that system is blocked, the pressure inside the eye (intraocular pressure) builds, which in turn damages the optic nerve. With the most common type of glaucoma, this results in gradual vision loss.
In angle-closure glaucoma, the angle formed by the cornea and the iris closes. In this illustration, the iris is plastered against the trabecular meshwork, which prevents the aqueous humor from reaching the drainage channels (see black arrow). This can lead to a rapid increase in intraocular pressure, a serious medical condition.