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Vision

2005-01-01 09:20:00

The sneak thief of sight?

QUESTION: My aunt has been diagnosed with glaucoma. What can you tell me about the disease?

ANSWER: Glaucoma is known as the "sneak thief of sight" 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.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.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.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. According to the National Eye Institute, glaucoma affects more than 2.2 million Americans age 40 and older, including more than 21,000 Kansans.