Retinal migraine (ocular migraine) is an eye condition that causes brief attacks of blindness or visual problems like flashing lights in 1 eye.
These episodes can be frightening, but in most cases they're harmless and shortlived, and eyesight goes back to normal afterwards.
Some people get retinal migraine every few months, although the frequency can vary.
Retinal migraine is a separate condition and should not be confused with headache-type migraine or migraine with aura, which usually affects the vision of both eyes.
The symptoms of retinal migraine may include:
It's unusual for an episode of vision loss to last longer than an hour. The same eye is affected every time in almost all cases.
Vision may slowly become blurred or dimmed, or there may be flashes of light. Some people see a mosaic-like pattern of blank spots (scotomas), which enlarge to cause total loss of vision.
If your eyesight suddenly deteriorates, make an emergency appointment to see an optician trained to recognise eye abnormalities and signs of eye disease (optometrist), your GP, or call NHS 111.
It's important to see an optometrist or medical doctor urgently if you suddenly lose your eyesight, particularly if it occurs for the first time. There are other more serious causes of sight loss that doctors will want to rule out.
If you manage to see a GP or optometrist during an attack, they may be able to see the decreased bloodflow to your eye using an instrument called an ophthalmoscope.
In this case the GP or optometrist may be able to make a confident diagnosis of retinal migraine.
However, as attacks are usually brief it's more likely you'll be diagnosed based on an account of your symptoms.
You may be referred to an eye specialist for tests to rule out other more serious eye diseases or stroke.
Retinal migraine is caused by the blood vessels to the eye suddenly narrowing (constricting), reducing the blood flow to the eye.
It may be triggered by:
Afterwards the blood vessels relax, bloodflow resumes and sight returns. Usually there are no abnormalities within the eye and permanent damage to the eye is rare.
Retinal migraine tends to be more common in:
Treatment for retinal migraine usually just involves taking pain relief for any headaches and reducing exposure to anything that might be triggering the retinal migraine.
Your doctor may sometimes prescribe medicine, such as:
However, there's still a lack of research about the best way to treat or prevent a retinal migraine.
There's a small risk that the reduced bloodflow may damage the thin layer at the back of the eye (the retina) and the blood vessels of the eye. This will be monitored in your follow-up appointments. Permanent vision loss is rare.