DEAR DR. ROACH: My husband woke up with double vision about three weeks ago. It appears that his left eye is turned inward and does not move with his right eye. He’s had a prescription for prednisone that did not help. An MRI has ruled out a brain tumor, and blood tests have ruled out myasthenia gravis.

An optometrist has prescribed prism glasses, which help a little. He’s been wearing an eye patch to drive short distances. His primary care provider indicates that it can get better with time, and he should just wait to see what happens. He has not hit his head or fallen. He’s 75 and in good health.

The only new medication he’s taken is Eliquis, which was prescribed about six months ago after he had a blood clot in his leg. The prescribing doctor indicated that he would only need to take it short-term, but his primary care provider seems to be reluctant to stop it.

I’m concerned that we’re not doing enough for his double vision. Do you have thoughts about its relationship to the blood thinner? — L.C.

ANSWER: Double vision, specifically binocular diplopia (seeing two images when both eyes are open and one image when either eye is closed), is most often caused by an inability for the eye muscles to move one eye, which seems to be the case with your husband. It sounds like the nerve that stimulates the muscle to move the left eye outward — the abducens or sixth cranial nerve — may not be working properly (which is called a palsy).

This isn’t definitive as there are many causes. Myasthenia gravis, an autoimmune neuromuscular disorder, is one, and unfortunately the blood test is not definitive as a minority of cases of myasthenia are seronegative. This means the blood test for the antibody that is attacking the nerve/muscle junction is not present.

The MRI was an essential test and is very reassuring. Not only does it make a brain tumor very unlikely, it also means the anticoagulant Eliquis is unlikely to be the cause, since a collection of blood around the eye could potentially block the movement of the eye. Eliquis, like all anticoagulants (“blood thinners”), can increase the risk of a serious internal bleed, but this would have been apparent by a CT scan or an MRI.

If he has what I think he has, there is a very good chance he will recover spontaneously. This good prognosis may be why it seems like they aren’t doing as much as they could. Still, if I were your husband’s primary care provider, I would enlist the help of a neuro-ophthalmologist.

DEAR DR. ROACH: I have a question about your recent column regarding kidney stones. I’m wondering if there was a typo. You said that diet is important with calcium-rich foods reducing the risk of kidney stones. You also mentioned that calcium supplements may worsen the risk of kidney stones. These two concepts seem inconsistent, and I am hoping to get clarification. — D.E.

ANSWER: The apparent paradox is explained by the amount of calcium and the timing in relation to food. Calcium-rich foods decrease kidney stone risk, probably because they bind the oxalate in the foods that cause the kidney stones when the oxalate is still in the intestines. This means less oxalate is absorbed, so there is less oxalate in the urine to form stones.

By contrast, calcium supplements may increase kidney stone risk because they are so concentrated that they cause temporarily high levels of calcium in the urine, which lead to calcium oxalate stones. If calcium supplements are absolutely needed, they should be small-sized and taken with meals multiple times daily. However, body calcium can be preserved by a thiazide-type diuretic that reduces calcium excretion.

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 ToYourGoodHealth@med.cornell.edu. (c) 2025 North America Syndicate Inc. All Rights Reserved