DEAR DR. DONOHUE: I am tormented by the possibility that I might have inadvertently harmed my own son. I committed myself to being the best mom possible. I read every baby book I could find. I took all the advice given me, including taking him for all the vaccinations suggested by the pediatrician.

It took many years, but he has been diagnosed with high-functioning autism. Lately I hear of a possible link between mercury in vaccination shots and autism. Could I have damaged my own child? – L.H.

Yours is indeed a heart-wrenching letter. The only thing you are guilty of is an admirable, deep love of your son. Would that all you could be found guilty of that.

The mercury story goes back to 1971, when grain imported into Iraq had been contaminated with methyl mercury. The mercury-tainted food caused 450 deaths and serious brain defects in infants whose mothers ate the grain while they were pregnant with these babies.

To prevent infections from vaccinations, thimerosal was added to vaccines. Thimerosal is ethyl mercury. It has never been shown to cause any problem that methyl mercury did. However, because of a theoretical risk – one never proven – thimerosal has been removed from pediatric vaccines. A few contain only trace amounts. There never has been evidence that supports the charges that thimerosal causes brain damage.

This topic, as would be expected, generates intense emotional debates. Readers who are unconvinced by the above explanation can read the entire story in the Institute of Medicine’s report on thimerosal at the Web site

DEAR DR. DONOHUE: As an ophthalmologist (retired), I wish to take issue with your glaucoma answer entitled “Glaucoma Creeps Up Slowly.” One important omission is that of closed-angle glaucoma. It comes on quickly. Furthermore, the rise of fluid pressure in the eye is seldom due to increased eye fluid production. Almost always it results from an impediment of eye fluid drainage. These points need emphasizing. – T.D., M.D.

The doctor is right-on. The rise of fluid pressure within the eye is almost always due to a blocked drainage system and not to increased fluid production.

This letter gives me a chance to delve into a neglected glaucoma story – closed-angle (also called narrow-angle) glaucoma.

Closed-angle glaucoma accounts for about 10 percent of all glaucoma cases. The angle is the juncture of the iris (the colored circle of the eye) with the cornea. It is at this spot where the eye’s drainage canal is located.

Closed-angle glaucoma often makes itself known with a sudden, painful attack of eye pain along with blurred vision, nausea and vomiting. The attack constitutes an emergency. If the fluid pressure is not quickly relieved, the optic nerve and eye can be permanently damaged, resulting in a loss of vision.

An ophthalmologist can create a fully open drainage canal with a laser. Once drainage is established, the danger has passed.

Thank you, Doctor, for your informative letter. I am saving it. It is so clearly and skillfully written that I should submit it for publication.

DEAR DR. DONOHUE: Lately, every place you look, you see something about coral calcium. What makes it so much better than other forms of calcium? – E.

DEAR DR. DONOHUE: I have been taking calcium for years. I am 75, and I have had a bone test that shows my bones to be quite healthy. I read about coral calcium and how wonderful it is. Do you think I should switch? – K.E.

Coral is a calcium reef that is built with calcium coming from a variety of marine life. Coral has some other minerals in it, such as magnesium.

Coral calcium is credited not only with providing calcium for osteoporosis prevention but for its power to prevent Alzheimer’s disease, diabetes and many other ills. Except for the osteoporosis prevention, there is no proof for these claims.

I find no convincing evidence that coral calcium is superior to any other calcium supplement.

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.

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