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Home > Education and Resources > Vision Loss

Glaucoma

Glaucoma is known as the "sneak thief of the night" because it has no symptoms, yet if untreated can cause blindness.

Glaucoma is a family of eye diseases that share one characteristic: increased pressure in the eye. Think of your eye as a sink, and glaucoma as having a clogged drain. As fluid is added to the eye, it builds up, causing increased pressure. As the pressure increases on the optic nerve, it kills nerve cells that transmit visual information to the brain.

People with glaucoma typically report no symptoms at first. Eventually, they lose their side, or peripheral, vision, and then central vision.

But most glaucoma can be managed and people can avoid vision loss. The keys are early diagnosis and proper management.

Who gets Glaucoma?

Like some other diseases, glaucoma can be age-related. People older than 45 are considered to be at higher risk than the general population. Genetics also plays a role. If your family has a history of glaucoma, you should consider yourself at risk.

One group that is at particularly high risk for glaucoma is African-Americans, who not only get the disease more often than other groups, but also get it earlier in life and in more severe forms. Glaucoma is the leading cause of blindness for African-Americans.

Other risk factors for glaucoma include diabetes, extreme myopia (nearsightedness), previous eye injury or regular use of steroids, such as Cortisone. If you belong to any of these groups you should have a regular eye exam.

Diagnosing Glaucoma

You should be tested for glaucoma as part of a normal eye exam. If you're in doubt about being tested, just ask your eye doctor.

There are three main ways your eye doctor tests for glaucoma. The most common is tonometry. In applanation tonometry, your doctor gives you eye drops with a mild anesthetic, and then gently touches your eye with a plastic prism in order to measure your intraocular pressure, the pressure inside your eye. In air tonometry, a puff of air is used to take the measurement. Since no objects actually touch your eye, no anesthetic is needed.

In the visual field test, your doctor tests your peripheral vision. You place your chin in a stand and look at a computerized screen. When you see a flash of light, you push a button. At the end of the test your doctor gets a graphic printout of how well you see across the visual field.

In ophthalmosocopy, your eye doctor uses a specialized instrument to look directly through your pupil at the optic nerve, where damage from glaucoma may be visually apparent.

Treatment

Glaucoma is one of the most treatable eye diseases. If you have the disease, chances are good you can manage it with medicine and have no further vision loss. The key to treatment is keeping your intraocular pressure under control. Your doctor has several tools available to achieve this goal.

Eye drops are the most common solution. The advantage of eye drops is that the medicine is delivered right where it is needed. If your doctor prescribes eye drops, remember to tell him about other medicines you take.

There are several categories of eye drops. Miotics help open the "drain" in the eye, increasing the flow of fluid from the eye. Beta-blockers slow down the rate of fluid into the eye. There are other, newer formulations that are also available that may be used in selective cases.

If eye drops don't control your intraocular pressure, your doctor may also prescribe pills. Carbonic Anhydrase inhibitors are taken orally and reduce the production of fluid into the eye.

Surgery can also be helpful in treating glaucoma. A kind of laser surgery, trabeculoplasty, can be done quickly and painlessly. The procedure causes some areas in the eye's drain to shrink, making other areas stretch open, thereby opening the eye's drain. Laser surgery can help up to 80 percent of all glaucoma patients avoid traditional surgery, and some patients are even able to discontinue some of their medications.

The most common traditional surgery is trabeculectomy. In this procedure, the doctor removes a small section from the trabecular meshwork, or the eye's drain. This makes it easier for fluid to flow out of the eye, reducing intraocular pressure. While there is a slightly higher risk of cataract forming after this surgery, it can be highly effective and many patients are able to discontinue eye drops and oral medicine.

According to the National Eye Institute, glaucoma affects more than 2.2 million Americans age 40 and older, including more than 21,000 Kansans.

Are You at Risk for Glaucoma?

The following groups are at greatest risk for developing the disease:

African-Americans over age 40
Everyone over age 60
People with a family history of glaucoma
People with high intraocular pressure
People who have diabetes, myopia, a previous eye injury, or who have long-term steroid or cortisone use

If you're in one of these risk categories, you should get a regular eye exam and make sure you're tested for glaucoma.

African-Americans Urged to get Checkups

No one knows why African-Americans are at greater risk for glaucoma than the general population. African-Americans also tend to get glaucoma earlier, and are more likely to lose their vision from the disease.

Glaucoma is the leading cause of blindness among African-Americans
Glaucoma occurs six to eight times more often among African-Americans than Caucasians
Glaucoma often occurs in African-Americans earlier in life
African-Americans between ages 45 and 65 are 14-17 times more likely to become blind from glaucoma than Caucasians with glaucoma in the same age group

For these reasons, all African-Americans over the age of 40 are urged to have an annual eye exam. If glaucoma is identified, it can generally be managed and its harmful effects limited.

Forms of Glaucoma

Primary open-angle glaucoma is the most common form of the disease, affecting about one percent of all Americans. Its cause is not known, but it may be hereditary. Primary open-angle glaucoma is characterized by increased intraocular pressure, which over time damages the optic nerve. There are no apparent symptoms with this form of glaucoma.

Normal tension glaucoma is also known as low-tension glaucoma. It harms your vision like primary open angle glaucoma does, but there is no increased intraocular pressure. Instead, it is caused by poor blood flow to the optic nerve. This form of glaucoma is increasingly being identified, and accounts for as much as one-third of all cases of open-angle glaucoma in the U.S.

Angle closure glaucoma is most common in people of Asian descent and in people who are far-sighted. People with this form of glaucoma have a smaller than normal anterior chamber and drain. This impedes the ability of aqueous humor to pass between the iris and lens. As fluid builds up, pressure is increased until it can no longer properly drain.

Acute glaucoma occurs when someone with glaucoma experiences a sudden increase in intraocular pressure. This may be triggered by stress, a physical injury, a medication interaction or when the pupil is extremely dilated (such as when in a darkened room). Acute glaucoma is an emergency condition and requires immediate attention from an ophthalmologist.