A patient contacted me when she suddenly started seeing double. She was seeing the same object as two images placed side by side. She didn’t figure in an accident, denies being hit on the head or eye and reportedly has no other health problems. She thought it would go away but it’s been two weeks and she was starting to get worried.

Believe it or not, this is not a rare occurrence. I’ve had several patients complain of the same symptoms and the same scenario, of a seemingly out-of-nowhere eye condition. Pretty scary so it’s something we should be wary of and see an eye doctor for.

As soon as the patient walks in to the clinic, the ophthalmologist already checks for head tilting or an unusual face position, such as a preference to look to the right. Vision is then tested. Sometimes, patients with double vision can have an accompanying blurring, giving early clues as to what may be causing the problem. Next, a complete eye exam is performed—pupils are checked, eyelids are examined for drooping, eye movements are tested for limitation or restriction. Eye pressure is also taken and a dilated retina exam is done to rule out other accompanying eye conditions.

In this patient’s case, her vision is good, 20/20 on both eyes. There was no drooping of the eyelids and her pupils both became smaller/constricted when light was presented. However, movements on the left eye were noted to be limited- the left eye was turned in toward the nose and was seen to be looking to the right. It could also not move to the left side even while eyes were advised to look and follow a moving object. The rest of the eye exam was otherwise normal.

Based on these findings, a likely explanation for her problem is a “stroke” in the blood vessel supplying the affected eye muscle, also known as a microvascular cranial nerve palsy. Risk factors for this condition are smoking, hypertension, and diabetes. Sometimes, doctors may recommend imaging, such as an MRI of the brain and the orbits for better evaluation of the eye and to locate the affected blood vessel.

The good thing about this eye problem is it resolves spontaneously in a few months’ time. The patients just have to wait it out. If the double vision affects activities of daily living, their eye doctor may recommend patching one eye to alleviate this. Smoking cessation of course is necessary as well as making sure blood pressure and blood sugar are well controlled.

In patients with eye muscle conditions whose pupils are also affected, further imaging is definitely warranted. It may mean other more sinister problems are present, such as a tumor in the brain. As always, if you’re unsure of your symptoms, best to consult your eye doctor.