What is Glaucoma?

Glaucoma is one of the leading causes of blindness in the United States today. Fairly common in adults over the age of 35, glaucoma threatens two out of every 100 persons in this age group. Glaucoma is often referred to as a thief in the night.
		Like a thief, glaucoma can rob you of your vision. Unfortunately, visual loss due to glaucoma cannot be restored. Even more disturbing is the fact that symptoms are often so gradual that many people fail to notice them, and early detection of glaucoma can arrest this disease, so that visual loss can be prevented. The best way to keep this thief in the night from robbing you of your vision is to have periodic eye examinations.

What does glaucoma do to the eyes?

When you look at an object, the picture is carried to the brain from the retina along a cable called the optic nerve. This cable contains many wires, each of which carry a message to the brain. These messages join together to provide side vision as well as sharp, central reading vision. An increase in pressure within the eye can damage some of these wires. Blind areas in the field of vision are often the result. This is often typical of glaucoma. The patient seldom notices these peripheral blind areas until considerable damage has occurred. If the entire nerve is destroyed, the result is total blindness.

What are the causes of glaucoma?

Think of the eye as a sink filling with water. Inside the eye, a transparent liquid known as the aqueous humor flows continuously, much like the sink with the faucet turned on all the time. If the drainpipe in the sink becomes clogged, water collects in the sink then overflows. Likewise, if the eye's drainage system is blocked, the water can't flow out. Instead, pressure increases inside the eye, and can eventually damage the optic nerve.

What causes this blockage?

Blockage of the eye's drainpipes can occur in three ways:

• First, the pipe may have been imperfectly manufactured. This type of problem is known as congenital glaucoma, and is present at birth. This condition is rare, and sometimes causes the front of the eye to become hazed, like fog on a windshield. An infant with congenital glaucoma may be sensitive to light and may tear excessively. When such conditions are apparent, the parent should consult a doctor.


• Second, debris or deposits can build up within the drainpipe, causing a partial blockage and a gradual increase in pressure inside the eye. This is known as chronic open-angle glaucoma because it develops slowly over a period of time. Most adult glaucoma patients have this type of glaucoma. Chronic open-angle glaucoma is seldom accompanied by symptoms, and can steal the vision so that the patient is unaware of trouble until the optic nerve is damaged.


• Third, inside the eye, the iris may close up the eye's drainpipe, much like a sheet of paper floating near the drain and suddenly dropping over the opening, blocking the drain entirely. Fluid then backs up and collects rapidly. This acute angle-closure glaucoma can cause blurred vision, severe pain, rainbow halos around lights, nausea, and vomiting. Unless this condition is relieved promptly, blindness can result in as little as a day or two.


• Injuries, drugs, hemorrhages, tumors, inflammations and other conditions can also block the eye's drainpipes and increase inner eye pressure, resulting in a form of glaucoma known as secondary glaucoma.

How can glaucoma be detected?

Early diagnosis of glaucoma can be made during a routine eye examination. During this painless exam, the doctor can determine the pressure level inside the eye. Sometimes, the visual field will also be tested for shrinkage or blind spots. Using an ophthalmoscope to view the back of the eye, the doctor will examine the optic nerve to make sure no damage is occurring.

Loss of vision is largely preventable

If you are over the age of 35, you should have your eyes checked for glaucoma every two to three years. Your eye doctor should be consulted whenever there is any decrease in vision or recurrent pain, or when any of the other symptoms discussed on this page are present. When diagnosed promptly, inner eye pressure can be brought under control and future glaucoma attacks can be prevented.

Are there contributing factors?

Many factors increase the risk of damage due to glaucoma. Among these are a history of glaucoma in the family and such general health problems as diabetes, anemia or arteriosclerosis. All these factors must be weighed before determining whether or not to begin treatment.

How is glaucoma treated?

All types of glaucoma need periodic observation and treatment. Most often, glaucoma can be controlled with the use of eye drops administered two to four times each day, or by pills given in various combinations. The purpose of this treatment is to decrease pressure in the eye, either by assisting the outflow of fluid from the eye or by decreasing the amount of fluid entering the eye. Glaucoma treatment through medication can sometimes result in undesirable complications and side effects. Some eye drops may sting, redden the eyes, and cause blurring of vision or occasional headaches. Such side effects usually disappear after a few weeks. Other drops may affect your pulse, your heartbeat, or your breathing. Pills can sometimes cause a tingling sensation in the fingers or toes, drowsiness, loss of appetite, bowel irregularities and occasional kidney stone formation. These medications are usually only prescribed when absolutely necessary. You should notify your doctor immediately whenever there is a question of possible side effects. FOLLOW YOUR DOCTOR'S ADVICE. Control of glaucoma by drugs can only be effective if patients adhere to the treatment schedule prescribed by the doctor. Medication should never be stopped without first consulting your doctor. It is always important to inform all physicians you visit about the eye medications you are taking.

Is surgery necessary?

If medications are poorly tolerated or ineffective in controlling pressure in chronic open-angle glaucoma, surgery may become necessary. The purpose of surgery is to form a new drainage canal in the eye. Acute-angle glaucoma is treated immediately with medications to lower the pressure and then by surgery or laser treatment.