Diagram of the normal eye

Glaucoma is one of the leading causes of irreversible blindness in the United States and in the world. It is a disease that typically affects older people, but it can occur at any age. Loss of vision is preventable if the disease is detected early and treatment is started.

The final pathway in this disease is the damage to the optic nerve. The eye has about 1 million tiny nerve fibers in the optic nerve, which run from the back of the eye to the brain. These nerve fibers allow us to see and provide us with full side or peripheral vision. Glaucoma is a disease which causes the destruction of these fibers. In the past, the loss of these nerve fibers was thought to be solely caused by high pressure in the eye. But now we recognized that there may be other causes of glaucoma because some patients with normal eye pressure can have glaucoma and loss of these nerve fibers.

In many patients, the disease is not noticed in the early stages, because there is no pain and no noticeable change in vision. The central vision is usually normal until the end stages and most patients are unaware of the slow and subtle loss of their peripheral vision. Early detection by an eye doctor is the key to the prevention of vision damage from glaucoma. Routine eye examinations, pressure check and evaluation of the optic nerve are recommended to treat and monitor glaucoma. Glaucoma cannot be totally cured; the treatment goal is to slow the progression of the disease to enable you to maintain useful vision in your life time.

Types of Glaucoma

The reason that eye pressure becomes elevated in glaucoma patients is that the drainage system in the glaucoma eye is not working properly. The fluid in the eye does not exit out of the eye as quickly as it should. The drainage system lies in a part of the eye called the angle, which is between the outer layer and the iris of the eye. The configuration of the angle helps determine the two general types of glaucoma; open or close angle.

The most common type of glaucoma is called primary or chronic open angle glaucoma. The drainage angle is open in these patients, but the eye fluid does not drain as quickly as it should. The pressure inside the eye builds up to a level which can damage the optic nerve and if left untreated, can lead to blindness.

Normal eye, fluid exits at the angle

In an open angle glaucoma eye, fluid is unable to exit at the angle

Closed-angle or narrow glaucoma occurs when the drainage angle closes, and almost no eye fluid can escape. During acute closed-angle glaucoma, eye pressure can get very high over a short period of time and there is severe pain. Angle closure glaucoma is an emergency and must be treated immediately. If the high pressure is allowed to continue for too long, permanent damage and even blindness can result. People who are at risk for angle closure glaucoma need to consult their eye doctor before taking certain system medications.

There are many other types of glaucoma, some responding better to certain medications and modalities of treatments. Your eye doctor or glaucoma specialist can help determine the type of glaucoma and prescribe the appropriate course of treatment.

Some people are more likely to have glaucoma. These include people who are older, nearsighted, diabetic, have a family history of glaucoma, have had past eye trauma, and other eye characteristics which your eye doctors can measure using sophisticated diagnostic instruments. Also, African-Americans are 5-7 times more likely to develop glaucoma.

Glaucoma is treated with eye drops that lower the pressure. If the pressure does not fall to a low enough level with drops, then laser or incision surgery may be necessary to achieve a pressure level that is safe for your eye.