DEAR DOCTOR K:

I was recently diagnosed with open-angle glaucoma. What can I expect in terms of treatment? Will the doctor be able to save my vision?

DEAR READER:

Our eyes are filled with clear fluid. In glaucoma, pressure builds up in the fluid. This increased pressure damages the optic nerve, which carries information from the eye to the brain. Because of the damage to the optic nerve, the information reaching the brain is reduced, and you cannot see as clearly.

In open-angle glaucoma, pressure tends to rise slowly over time. Gradual loss of vision is usually the only symptom. Because vision is lost painlessly and gradually, most people don't realize they have a problem until substantial damage has occurred. Last year, a close friend of mine discovered in a routine eye exam that glaucoma had produced some permanent damage to her vision. Fortunately, she caught it relatively early.

The good news for her and for you is that proper treatment of glaucoma can prevent further loss of vision -- although it won't restore vision that has already been lost. On the other hand, untreated glaucoma can lead to permanent blindness.

Treatment usually begins with prescription eye drops. These medicines lower pressure inside the eye.

Laser surgery can be done as an alternative to medication, or when medication fails to control glaucoma. This surgery is called laser trabeculoplasty. Eye surgeons perform this procedure in an office or eye clinic. A high-intensity beam of laser light carefully widens openings in the eye's drainage system to increase the amount of fluid that drains. When a little fluid drains out of the eye, the pressure drops.

If both medication and laser surgery fail, eye surgery may be necessary. In this procedure, which is performed in an operating room, the eye surgeon will apply numbing medication on and around your eye. He or she will create a new opening to improve fluid drainage. Eye pressure almost always decreases with either laser or conventional surgery.

In most cases, eye drops alone will successfully lower eye pressure and protect your eyes against further damage. So the most important thing you should know about glaucoma is that it should be diagnosed early, before it starts to damage your eyes.

Glaucoma is like some other diseases -- high blood pressure, for example -- in that it causes damage without causing symptoms. The only way to know that you have glaucoma is to have your eye pressure measured regularly. Also, an eye professional should look at the shape of your optic nerves, since glaucoma can sometimes change the shape of the nerves before it raises eye pressure.

There is no expert consensus on how often a person should be screened for glaucoma. My advice to patients is that they have the screening after reaching age 40. If their eye pressure or the appearance of their optic nerves is close to being abnormal, I recommend repeating the screening every several years. My friend who discovered she had glaucoma had not had her eyes examined in a long time -- too long.

(Dr. Komaroff is a physician and professor at Harvard Medical School. Go to his website to send questions and get additional information: www.AskDoctorK.com.)

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