The condition is also sometimes called an ophthalmic migraine, visual migraine, or an ocular migraine, although symptoms for these are slightly different.
A retinal migraine can cause temporary blindness or visual problems in one eye. Retinal migraines usually last for up to 1 hour and are followed by the return of normal vision.
Causes of a retinal migraine
A retinal migraine is caused by a reduction in blood flow to the eye when blood vessels narrow suddenly. There are several reasons why this might happen.
A retinal migraine starts with visual disturbances in one eye.
Factors that might trigger blood vessel narrowing and retinal migraines include:
- Bending over
- Birth control pills
- Excessive heat
- High altitude
- High blood pressure
- Low blood sugar
As the blood vessels relax and blood flow returns to normal, the symptoms usually disappear and vision comes back.
Some people are more at risk of a retinal migraine than others. These people include:
- People aged 40 years and under
- Individuals with a family history of migraines
- People with another condition, such as atherosclerosis, epilepsy, lupus, and sickle cell disease
It affects women more often than men.
Retinal migraines involve repeated attacks of certain visual disturbances. These usually happen before the headache phase of a migraine. The visual disturbances are often collectively referred to as "aura."
Symptoms occur in one eye. The characteristics of an aura may include:
- Seeing flashing, sparkling, or twinkling lights
- A blind spot or partial loss of vision
- Temporary blindness
The aura may spread gradually over 5 minutes or more and last for 6-60 minutes. Within 60 minutes of visual symptoms, the headache phase of a retinal migraine may begin.
The headache phase of a retinal migraine has symptoms like a migraine without aura. These symptoms include a headache that lasts 4 to 72 hours on one side of the head.
The headache may be:
- Pulsing or throbbing
- Moderate to severe in pain intensity
- Made worse by activities such as walking or climbing stairs
A migraine headache may also cause:
- Nausea and vomiting
- Increased sensitivity to light
- Increased sensitivity to sound
A migraine with aura is a different condition to a retinal migraine, although some of the symptoms are similar.
Migraines with aura also cause visual disturbances such as flashes of light, blind spots, and other visual changes. However, a retinal migraine differs from a migraine with aura for two main reasons:
- The visual symptoms only occur in one eye and not both
- Complete but temporary blindness may occur in one eye only
There are no diagnostic tests that detect a retinal migraine. A doctor may diagnose a retinal migraine by examining personal and family medical history, asking about symptoms, and conducting an examination.
Other possible causes for the symptoms will be ruled out before a retinal migraine is diagnosed. It is important to investigate and rule out other causes of temporary blindness.
A specialist doctor might need to ensure that the symptoms are not caused by a serious eye disease or stroke.
Some people that have visual disturbances in one eye might have hemianopia. Hemianopia is the loss of vision on the same side in both eyes. This condition often happens in stroke and traumatic brain injuries.
The medication that a doctor prescribes to treat retinal migraines may change depending on a person's age and how frequently they have retinal migraine attacks.
Prescribed medication might include:
NSAIDS such as ibuprofen or aspirin may relieve the pain of the headache.
- Non-steroidal anti-inflammatory drugs (NSAIDs), such as aspirin or ibuprofen, to relieve pain and inflammation
- Antinausea medications to prevent nausea and vomiting
- Ergotamines to narrow blood vessels in the brain to relieve a headache
- Triptans to narrow blood vessels in the brain and reduce swelling
- Beta-blockers to relax blood vessels in the brain
- Calcium channel blockers to prevent blood vessels constricting
- Antidepressants to help prevent a migraine
- Anticonvulsants to help prevent a migraine
There is currently a lack of research into the best way to treat a retinal migraine. However, most treatments focus on pain relief for headaches and reducing exposure to potential retinal migraine triggers.
There is a small risk with a retinal migraine that the sudden reduction in blood flow to the eye may damage the retina and blood vessels of the eye.
The medications that are used to treat a retinal migraine can sometimes cause other problems.
- NSAIDs may cause stomach pain, bleeding, ulcers, and other problems
- Medications can cause overuse headaches if an individual uses them for more than 10 days a month for 3 months
- Serotonin syndrome is a rare, life-threatening condition that has an increased risk in people that combine certain antidepressants and triptans
The permanent loss of vision following a retinal migraine is rare.
Most people that have retinal migraines will usually experience an attack every few months. The visual disturbance phase tends to last no more than an hour, and the subsequent headache can last anywhere from a few hours to a few days.
A retinal migraine is difficult to diagnose. It is often misdiagnosed as another condition or as a common migraine. While there is no cure for the condition, it can be managed and prevented through medication and avoiding triggers.
Currently, retinal migraines are not fully understood, but research is ongoing. The investigation into migraine prevention is in progress, but, as yet, there is no proven cure.