DEAR DR. ROACH: I am a healthy 58-year-old female. One year ago, I was sitting on a friend’s porch when suddenly it was as if someone had poured thick oil over my left eye. After consulting with my eye doctor and my family physician, the occurrence was diagnosed as an ocular migraine. Bloodwork and a routine physical turned up nothing abnormal. Both doctors said it was nothing to worry about and that it most likely would not occur again. However, I have an episode about every three to four months. Always the left eye, and it always clears up within five minutes. What is your take on this? — J.M.

ANSWER: Your doctors may be right, but I’m not 100 percent convinced, based on what you have told me. Temporary loss of vision (called amaurosis fugax, from Greek and Latin roots) can be caused by several conditions, some of which are sight-threatening. But there are three particularly important causes that I think of in your case.

The first is a blood vessel problem, most commonly an embolus (a small piece of debris, such as cholesterol plaque or blood clot) that blocks the artery to the retina. This usually lasts from a few seconds up to 15 minutes, and people classically describe it as a curtain coming over the eye, sometimes with complete blindness and sometimes with only grayness over the vision.

Ocular or retinal migraine is a second possibility. These usually first occur in people who are under 40, often those with a family history. Some people describe “scintillation” in the visual field. These last five minutes to an hour or so, and are followed by a headache within an hour. You are older than most people when diagnosed by this, and you didn’t describe the headache, which makes this diagnosis less likely, although still possible.

In addition, I would be concerned about temporal arteritis, also called giant cell arteritis. Vision loss is not usually the first symptom of this inflammatory disease (headache and a painful sensation after chewing a short while are the usual symptoms), but vision loss can be permanent and is almost always preventable if the diagnosis is made and treatment begun promptly.

A complete physical is a good start. An exam by an ophthalmologist is essential. Blood testing for temporal arteritis may not have been part of the routine blood work you received. As you are 58, most experts would obtain an ultrasound or MRI of the carotid artery to look for a source of embolism, and would at least consider an echocardiogram and MRI of the brain. The diagnosis of retinal migraine is made only after being sure there isn’t something else causing the vision loss.

DEAR DR. ROACH: I have a twitching of my left eye. My face draws up when it happens. I went to a doctor and he gave me 15 Botox shots around my eye and said I will need them every three months. They help some. Can you tell me what it could be? — F.G.

ANSWER: This is a special type of dystonia, a movement disorder, called blepharospasm (blef-a-row-spasm). It’s an involuntary contracture of the orbicularis oculi muscle, which goes around the eye. Other muscles may be involved, giving your face the “drawn up” appearance.

The botulinum toxin the doctor injects you with partially paralyzes the muscle, preventing the spasms, but the toxin wears off. The condition is common, but in most cases is mild enough or intermittent enough that such powerful treatments aren’t needed. In a few cases, surgery is required.

You can get more information about blepharospasm and other dystonias at www.dystonia-foundation.org.

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 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.