DEAR DR. DONOHUE: How does one get double vision? How does one get rid of double vision? I have been told by a friend that an ear infection, which I had, could have given me double vision. Is this true? – M.S.

ANSWER: No, an ear infection is not a usual cause of double vision. Our two eyes give us good depth vision, but they also bring the seeds of trouble. Each eye sends to the brain an image that is slightly different, since each views things at a different angle. The brain has to fuse those slightly different images into a single picture, and eye muscles have to keep both eyes in line to achieve a difference that’s only slight. If the eye muscles, however, aren’t aligned perfectly, the brain can’t merge the two images, now seen at a greatly different angle, into a unified image. Double vision results. Quite often, the eye muscle misalignment is due to nerves misfiring. Nerve malfunction or muscle misalignment occurs for many reasons – head trauma, diabetes, tumors, aneurysms, Graves’ disease (an overactive thyroid gland) and the nerve condition called myasthenia gravis. Looking with only one eye abolishes this kind of double vision – binocular double vision – even when the diverging eye is the eye used for vision.

Less frequently, double vision comes from a problem of the eye itself. Something goes wrong with the cornea or the eye lens. The cornea is the transparent covering of the eye. A corneal scratch or any irritation can distort vision to produce two images. And a number of lens problems make people see double. The lens is the crystal-clear, focusing disk behind the pupil. Cornea or lens problems produce monocular diplopia, “diplopia” being the medical word for double vision. Monocular diplopia is not common. It does not clear when a person uses the affected eye to see while the good eye is closed.

Correction depends on finding the cause, and you can do that only with the help of your family doctor, who might want the opinion of an eye doctor or a neurologist. If no cause is found, a special lens for glasses can often fuse the two images into one.

DEAR DR. DONOHUE: Thirty-two is young to have high blood pressure, isn’t it? That’s my age, and I’ve got high blood pressure. I didn’t know I had it, but my gynecologist found it when I went for a Pap smear. He sent me to an internal-medicine doctor, who thinks I might have aldosteronism. He’s doing a bunch of tests for it right now. I know this has something to do with the adrenal gland, but that’s all I know about it. What is it? – R.C.

ANSWER: Thirty-two is young to have high blood pressure. That’s probably the reason that prompted your doctor to look for rare causes of hypertension. High blood pressure at young ages turns thoughts to seldom-seen causes. Aldosteronism is one of those causes.

The adrenal glands make a number of hormones. One of them is aldosterone, a hormone that regulates the potassium blood level and contributes to blood pressure control. Too much aldosterone raises blood pressure and lowers blood potassium. A noncancerous tumor of the adrenal gland is the principal cause of aldosteronism.

One of the bright aspects of aldosterone-caused high blood pressure is that it is curable with removal of the tumor.

DEAR DR. DONOHUE: Is it true that the body has to be on the alkaline side to maintain good health? I have friends who talk about this all the time. They are quite careful about eating alkaline foods and avoiding acid foods. All of this is foreign to me. What do you think about it? – W.B.

ANSWER: Alkalinity is the opposite of acidity. The pH scale tells if a material is acid, alkaline (basic) or neutral. A pH of 7 indicates neutrality. Numbers higher than 7 are alkaline, and those less than 7, acid. Normal body pH is 7.4, slightly alkaline.

Healthy people don’t have to fret about their alkalinity or acidity. Nature has given us kidneys and lungs that regulate body pH so it stays right where it should be. You don’t have to follow a special diet.

DEAR DR. DONOHUE: To join the swimming team, my son had a physical exam. The doctor called my husband and said our son has a heart problem. He wanted the boy to see a cardiologist, and my husband took him to the suggested doctor. Our son has coarctation of the aorta. More tests have to be done, but the heart doctor says an operation will be necessary. What is this all about? – V.T.

: The aorta is the main artery. It arises from the heart and travels from there to the bottom of the abdomen, where it divides into two arteries for the legs. Throughout its course it gives off branches that supply the entire body with blood. A coarctation is a constriction of the aorta at a spot that’s not far from its origin near the heart. Think of it as a kink in a hose. In some youngsters with the defect, there are no symptoms until later in life. In a few, it produces alarming symptoms early on.

One of its tip-offs is high blood pressure in the arms with low blood pressure in the legs. The high arm blood pressure comes about because the arteries to the arms spring from the aorta before the kink. The leg arteries come after the kink and, therefore, have a lower blood pressure. Most of the time, there is also a murmur heard when the doctor listens to the chest with a stethoscope.

Surgery corrects the kink. If your son is proven to have this defect, he should have the surgery without too much delay. The high blood pressure in the upper half of his body can do permanent damage if it’s not corrected. This condition is one that is usually completely correctable.

Dr. Donohue regrets that he is unable to answer individual letters. Readers may write him at P.O. Box 536475, Orlando, FL 32853-6475. Readers may also order health newsletters from

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