DEAR DR. ROACH: I went to the ophthalmologist to have my eyes evaluated. After a series of tests, he told me that I have a cataract and normal eye pressure, but I also have a rare inherited disease called pseudoexfoliation. He said it will cause many complications if I have cataract surgery, and then he walked out before I could ask him what the disease involves. I went home and looked it up on the web. I totally frightened myself with what I read. I know sometimes the web isn’t the best source for medical advice, but since he left me with no knowledge of the situation, I wish you could explain what it is and what the implications are. — E.H.

ANSWER: Pseudoexfoliation syndrome causes the deposition of white, fluffy protein material in the front part of the eye. It is rare in young people, but is present in about 5 percent of people between 75 and 85. There is indeed a strong familial component to the condition, and a gene has been identified.

It increases the risk of cataract, but especially increases the risk of glaucoma, with excess pressure in the eye. Both cataract and glaucoma treatment are more challenging in the case of pseudoexfoliation syndrome, but cataract surgery still can be done, with low risk, by an experienced surgeon.

It may be that your cataract is not yet bad enough to merit surgery; however, if you are having significant vision problems because of the cataract, it might be worthwhile to find an expert in cataract surgery with pseudoexfoliation syndrome.

About 15 to 30 percent of people with the syndrome will develop glaucoma, so you will need to see an eye specialist frequently to keep a careful eye on your pressure, and possible treatment (usually eyedrops) to prevent glaucoma.

The booklet on macular degeneration explains a very common eye ailment. Readers can order a copy by writing: Dr. Roach Book No. 701, 628 Virginia Dr., Orlando, FL 32803. 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. ROACH: I am an 84-year-young Caucasian man in good health. In college, I donated blood and was told I was Type O-negative. Later in life, I donated many pints to the Red Cross. About 45 years ago I was told by the Red Cross that my blood type had changed to O-negative Du-positive, and a year ago I received a letter saying I am now Type O-positive. How can this be? — F.D.

ANSWER: Your blood type hasn’t changed, but the way you are classified has. A and B are proteins on the red blood cell, and although you have neither of these proteins (making you Type O), other people have one (Type A or B) or both (Type AB), since ABO blood type is based on the proteins on the blood cells. The ”positive” or ”negative” in blood typing refers to the Rh factor, which is not one but several different proteins. D is the most important of these. Your Rh factor — ”Du,” also called ”weak D” — is a weakly positive Rh D factor. Less than 1 percent of people have this. Blood banks have not always been consistent in how this is reported. Since it’s possible for a person who is Rh-negative to react to even a weakly positive Rh D factor, it is safest for potential recipients to consider your blood Rh-positive. You also are likely to be safe getting Rh-positive blood.

People with a blood protein can get red blood cells from people without that protein, so people with Type O-negative blood can donate to anybody, while someone with blood Type AB-positive can get blood from anybody. (That’s a bit of an oversimplification, since there are other less-common proteins that get crossmatched by a modern blood bank.)

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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 [email protected] or request an order form of available health newsletters at 628 Virginia Dr., Orlando, FL 32803. Health newsletters may be ordered from www.rbmamall.com.

(c) 2016 North America Syndicate Inc.

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