Going blind in one eye? It could be retinal migraine!

Retinal migraine is a sub-type of migraine that affects the eyes.

Imagine you are going about with your work and suddenly you black out in one eye. A throbbing headache follows the sudden blindness, and then, minutes later, the vision returns. The episode of blindness in one eye may be temporary but it is a nightmarish situation for someone undergoing it. And the throbbing headache, however, lasts for five hours or more.

This sudden black out in one eye with a splitting headache is called retinal migraine. "Retinal migraine is also know by other names such as ophthalmic migraine or ocular migraine. Since there is headache involved, I consider it a subtype of migraine," says Dr K Ravishankar, renowned headache management specialist who runs The Headache and Migraine Clinic, at Jaslok and Lilavati Hospital, Mumbai.

What are the symptoms of retinal migraine?

There is a temporary vision loss or scotoma in one eye. The vision loss may be complete or partial and usually doesn't last for more than an hour.

The blindness may be complete or partial.

Vision loss is accompanied by a headache. "The ache may happen before the vision loss, during the vision loss and sometimes, rarely, after the vision loss," says Dr Ravishankar.

The visual disturbance usually occurs on the same side as the headache.

The sudden vision loss is bound to frighten anyone, but that shouldn't alarm you says Dr Ravishankar. "The vision loss is temporary and the person usually recovers from the blindness."

Is it the same as visual migraine with a visual aura?

Some people who frequently get migraine report seeing bright lights and squiggly lines in front of their eyes. But it is often not the same as the retinal migraine says Dr Ravishankar. "Migraine with aura is a completely different entity. It is not accompanied by partial vision loss," says the doctor. "The coloured lights, bright spots and the lines are usually symptoms in keeping with migraine with aura."

However, some overlap is seen between retinal migraine and migraine with aura says the doctor. "In 25 percent of retinal migraine cases, some symptoms of migraine with aura can be seen." Like migraine with aura, retinal migraine may also present effects like nausea, vomiting, and light and sound sensitivity. "There is more vision loss in retinal migraine and more bright lights, squiggly lines -- what we call positive visual phenomenon-- in migraine with aura," he adds.

Who is at risk for retinal migraine?

It is common in people who have a history of migraine attacks.

"It is seen mostly in women in their 20s and 30s," says Dr Ravishankar. "So one doesn't know whether oestrogen plays a role or not," he says.

It can happen to someone who has a family history of retinal migraine. "Migraine is genetic, but that doesn't always mean if the parents have retinal migraine, the child will have it too," says Dr Ravishankar.

What causes retinal migraine?

"It is a migrainous phenomenon which is caused by a spasm of the blood vessel," explains Dr Ravishankar. When the blood vessel gets constricted for whatever reason, the blood flow to the eye is cut off. This can trigger an episode of retinal migraine. When the spasm stops and the blood flow returns to normal, the vision in the eye returns slowly.

How is retinal migraine diagnosed?

There is no diagnostic test for retinal migraine. The doctor will try to rule out other underlying causes. "The patient should remember that if there is a vision loss, he or she shouldn't self diagnose it as retinal migraine. A thorough investigation is required to rule out other underlying reasons for the blindness such as tumors or blood clots."

"The doctor may do an eye check up along with MRI scans, Doppler scans, ultrasound, angiography or CT scans to detect any kind of mass behind the eyes. A blood checkup may also be required to determine if there is thickening of the blood or a travelling clot in the blood vessel," says Dr Ravishankar.

How is retinal migraine treated?

The medication for retinal migraine is same as that for migraine. "In some patients, aspirin a blood thinner, is used especially if a clot-like mechanism is causing it," says Dr Ravishankar. "Since it causes a lot of panic due to the blindness, everyone uses aspirin to treat it. But it should actually be treated with anti-migraine drugs," he concludes.

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