Narrow angle glaucoma calls for an immediate laser iridotomy
DEAR DR. ROACH: My eye doctor told me I'm in danger of an "acute attack" of narrow angle glaucoma and that I need iridotomy in both eyes right away. He also said this may be related to my headaches. I wanted to get a sense of whether to go ahead with it pretty quickly or to possibly get a second opinion, since this ophthalmologist is new to me. I'm kind of nervous about it, since it seems that only about 65% of folks are "cured," with others sometimes needing a follow-up surgery later on. -- G.M.
ANSWER: Glaucoma is a disease of the retina, most often associated with elevated pressures inside the eye. The fluid inside the eye (in the part of the eye called the aqueous humor) drains through structures in the eye called the trabecular meshwork. In some people, the flow of fluid in the aqueous humor is limited, and can even be completely obstructed by the root of the iris (the colored part of the eye), causing very high pressures and an immediate threat to sight. Unless the pressure is relieved, vision can be lost permanently within hours.
I have had patients who have been told they need laser surgery right away to prevent acute closure, and I have always advised them to get the procedure. The procedure uses a laser to make a tiny hole in the iris to allow fluid to go through, even if the angle closes the trabecular mesh. This prevents an emergency from happening in the first place. Moreover, people like you who are at risk for acute closure of the angle may gradually develop vision loss they won't even realize, since the vision loss in glaucoma is at the periphery of one's vision, where it may not be noticed. Finally, doing the laser iridotomy before scarring occurs gives a better prognosis, making it less likely to need daily medication afterward or a follow-up surgery (90% of people treated early did not need medication or follow-up surgery in one study).
Until you get surgery, you should avoid medicines that contain warnings for people with glaucoma: This especially includes cold medicines with pseudoephedrine (Sudafed) and similar decongestants, some antidepressants, and some antihistamines.
DEAR DR. ROACH: I am a 79-year-old female who had quadruple bypass surgery and had a stroke during surgery, resulting in significant vision loss. Is there a high risk for another stroke if I undergo knee replacement surgery? -- S.T.
ANSWER: People who undergo cardiac bypass surgery are at high risk for stroke during surgery. This is for several reasons: One is that people with frequent blockages in the arteries of the heart also have blockages in the blood vessels to the brain. But, in addition, the use of cardiopulmonary bypass allows for the possibility of small pieces of arterial plaque or blood clots to surface, which can be released during surgery and flow into the brain, causing strokes. A relatively lower blood pressure to the brain during the time a person is on the heart-lung machine also predisposes to a stroke during cardiac surgery. A stroke is still possible, despite the very best care.
The risk for you to have another stroke during noncardiac surgery, such as a joint replacement, is much, much less than it is with cardiac surgery requiring the cardiopulmonary bypass machine. There is still a small risk of stroke, and you should get more information from your regular doctor or your neurologist. But, most people do very well with joint replacement procedures.
Dr. Roach regrets that he is unable to answer individual letters, but will incorporate them in the column whenever possible. Readers may email questions to ToYourGoodHealth@med.cornell.edu or send mail to 628 Virginia Dr., Orlando, FL 32803.
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