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Ask the doctor: Did a stroke damage my vision?

Ask the doctor

Did a stroke damage my vision?

Q. A few months ago I gradually lost about 50% of the vision in my right eye. My ophthalmologist says this was caused by a small stroke. Am I now at higher risk for future strokes or heart attacks than someone who has not had a stroke?

A. It sounds like you had a retinal artery embolus rather than a stroke, which would have affected both of your eyes. That technicality aside, the implications for your future are essentially the same as if you did have a small stroke.

A retinal artery embolus occurs when a small clot or bit of plaque from your heart or an artery elsewhere in the body gets into the bloodstream and sticks in one of the small arteries that supply your retinas. This material is called an embolus (plural, emboli). The embolus cut off the blood supply to your right retina for a while, and the resulting lack of oxygen caused some damage. This is essentially what happens in a heart attack or stroke, only on a smaller scale.

As you have guessed, you are indeed at higher risk for another embolic event, particularly for the next year or so. The embolus is almost certainly a sign that you have atherosclerosis, which tends to affect many arteries throughout the body, not just the coronary arteries. That puts you at higher risk of having a heart attack or stroke.

The most crucial thing for you to discuss with your doctor is whether you have any obvious treatable causes of the problem. Some of the maj­or ones that can be addressed include untreated or inadequately treated high blood pressure, cholesterol-clogged carotid arteries, or atrial fibrillation, the erratic rhythm of the heart's upper chambers that causes clots to form in the heart.

Sometimes no single obvious cause can be found, even after considering a long list of potential problems. In this case, taking a daily low-dose aspirin to prevent small clots from forming in the bloodstream makes good sense. Your doctor may also recommend other medications or stroke-preventing strategies.

One key thing for you is to have confidence that your doctor has considered all of the possibilities and explained them to you. If you aren't sure he or she has covered all of the bases, get a second opinion from a stroke specialist or a cardiologist. More information isn't going to hurt you, and the stakes are always high in stroke prevention.

— Richard Lee, M.D. Associate Editor, Harvard Heart Letter

Last updated:	September 05, 2008