DEAR DR. DONOHUE: Five years before my mother died, she developed macular degeneration. Poor vision made her last years quite difficult. How will I know if I have the beginnings of it? Can I do anything to prevent it? – E.K.

ANSWER: The macula is a small, round spot on the retina that permits us to see details clearly – people’s faces, newspaper print and thread for sewing. Without a healthy macula, people cannot read, cannot drive and have great difficulty watching TV.

One simple test for detecting the onset of macular degeneration is the Amsler grid. It’s a card with intersecting horizontal and vertical lines. If, when looking at the center of the grid of lines, the lines are wavy or crooked, that’s a sign of macular degeneration. You can make such a card for yourself by drawing a series of horizontal lines on a 3-inch-by-five-inch card and then turning the card and drawing another set of lines that intersect with the first set.

The cause of macular degeneration isn’t fully known. Age is one cause. Smoking is a factor. Ultraviolet light might be involved. Caucasians have the condition more than other races. Genetics plays a role, but having had one parent with it doesn’t destine you for it.

Prevention? Don’t smoke. Wear sunglasses that filter out ultraviolet rays. If the condition starts, taking a pill containing vitamins C and E, beta carotene, zinc and copper can slow its progression.

I’ve been talking about the dry kind of macular degeneration. It’s the more common kind, and it usually progresses slowly. Wet macular degeneration causes a much more rapid deterioration of vision.

The booklet on macular degeneration discusses both types in depth. Readers can obtain a copy by writing: Dr. Donohue – No. 701, Box 536475, Orlando, FL 32853-6475. 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: There’s a white patch on the side of my tongue that I brought to the attention of my dentist. He said it is leukoplakia and that I should have a biopsy. I’m putting it off because he said it could go away on its own, and it doesn’t bother me in the least. What are your thoughts on the biopsy? – K.O.

ANSWER: Get it done.

Leukoplakia comes in various shapes and sizes, and is found on the lips, gums, inner cheeks and the sides of the tongue. It can be a sign of cancer changes, or it can be a sign only of an irritation. The difference cannot be told by looking at the patch. The only way to discover its true nature is to examine a biopsy specimen with a microscope.

You’re possibly putting yourself in hot water by dallying.

DEAR DR. DONOHUE: I have had to take four different medicines for asthma. My doctor put me on Symbicort, and it takes care of everything for me. Would you mention this in your articles? – J.

ANSWER: Symbicort is an inhaler medicine composed of budesonide (a cortisone medicine) and formoterol (a beta activator medicine). Cortisone drugs soothe inflamed airways, and beta activators dilate them. I’m glad this combination works so well for you. What works for one doesn’t always work for another.

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