DEAR DR. DONOHUE: Every year I have two exams, one for my heart and lungs and the other for my eyes. I am 67 and take only a blood pressure medicine. My pressure isn’t all that high.

Two weeks ago, I got a real jolt. The eye doctor told me I have glaucoma and to begin using drops. He says my eye pressure is quite high. Is this related to high blood pressure? I see perfectly without glasses except for reading glasses, and have no eye pain. What can you tell me about glaucoma? — C.C.

ANSWER: Older people are urged to have frequent eye exams for the exact reason you give — the detection of glaucoma, which is silent early on but progresses and leads to irreparable loss of sight.

The front third of the eye is a space called the anterior chamber. Fluid, produced by the eye, fills that chamber and provides nourishment for that part of the eye. The eye makes the fluid and also drains it away. If the drainage system becomes plugged, fluid pressure in the anterior chamber builds up. This pressure has nothing to do with blood pressure. The increased pressure compresses the optic nerve in the back of the eye. That nerve brings incoming visual signals to the brain. It’s the brain that sees for us. Nerve compression damages the nerve.

Early on, glaucoma has no symptoms. As time passes, vision off to the sides is lost, and the person’s sight becomes similar to the sight one has when looking through a narrow tunnel. If measures are not taken to halt the process, vision goes. Blindness from glaucoma is preventable.

Eyedrops usually are the first medicines for lowering eye pressure. If they don’t get the job done, then a laser beam can open up the eye’s drainage system. Should that fail, surgical correction of the drainage channel is the next step. I have talked only about open-angle glaucoma, the more common kind of glaucoma.

TO READERS: The Pap smear has reduced the number of women who develop cervical cancer. The booklet on those two topics, Pap smears and cervical cancer, gives a comprehensive understanding of both. To order a copy, write: Dr. Donohue — No. 1102, Box 536475, Orlando, FL 3285306475. Enclose a check or money order (no cash) for $4.75 U.S./$6 Can. with the recipient’s printed name and address. Please allow four weeks for delivery.

DEAR DR. DONOHUE: We have just installed a water softener because our water supply is a well with hard water. I understand that a water softener adds sodium to the water. I am watching the amount of sodium I get because I have high blood pressure. Was the softener a good idea? — P.P.

ANSWER: Magnesium and calcium are two minerals that make hard water hard. To soften water, those minerals are removed and replaced with sodium.

All of us are benefitted by reducing our sodium intake. Experts advise not getting more than 1,500 mg of sodium a day. The average amount of sodium in a liter (1.06 quarts) of softened water is about 270 mg. Even if you drink two liters (2.12 quarts) of water a day, you’re taking in 540 mg of sodium, one-third the daily allowance. I doubt very much if you drink that much water a day. The water softener isn’t a bad idea.

If you want to know the exact amount of sodium in your water, contact the manufacturer of your water softener.

DEAR DR. DONOHUE: What’s the feeling on using magnets to treat arthritis? I have knee arthritis bad. My cousin, who has the same problem, says magnets have turned her life around. Before she started using them, she hobbled around. I’d like to try it. — W.S.

ANSWER: Evidence for the effectiveness of magnets in controlling osteoarthritis, the most common kind of arthritis, is based mostly on statements from satisfied users. That’s not reliable proof. I have doubts about them. However, if you want to give them a try, they won’t hurt you, so long as you don’t abandon any therapy you might now be taking.

Dr. Donohue regrets that he is unable to answer individual letters, but he will incorporate them in his column whenever possible. Readers may write him or request an order form of available health newsletters at P.O. Box 536475, Orlando, FL 32853-6475. Readers may also order health newsletters from www.rbmamall.com.

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