Sudden sparkling lights, shifting shapes or a growing gap in your vision can be alarming. While new visual symptoms should always be discussed with your doctor, these temporary visual disturbances are sometimes caused by an ocular migraine, also known as a visual aura or migraine with aura.

What Are the Symptoms of an Ocular Migraine?

Symptoms usually develop gradually. Common visual symptoms include:

• Shimmering or flashes of light
• Moving dots, sparks or geometric shapes
• Wavy or zigzagging patterns, sometimes resembling colorful prisms that move across your field of vision
• A growing blind spot
• Blurred or distorted vision
• Temporary difficulty reading or recognizing faces

A migraine headache may begin during or after the aura and can include nausea, light sensitivity or sound sensitivity. About 25% of people who have migraines experience migraine with aura.

Some people experience migraine with aura without any head pain. In these cases, visual symptoms may be the only sign of a migraine episode.

“The wave of electrical brain activity does not always trigger the migraine pain pathway,” says Katherine S. Carroll, MD, a neurologist at Northwestern Medicine.

Fortunately, most ocular migraines follow a predictable pattern and resolve quickly.

How Long Does an Ocular Migraine Last?

Visual aura usually develops gradually and resolves within 60 minutes. Most episodes last about 20 minutes.

When symptoms start:

• Stop what you are doing and move to a safe spot.
• Avoid driving or operating machinery.
• Rest your eyes, dim bright lights and turn away from screens.
• Drink water, especially if dehydration may be a trigger.

What Causes Ocular Migraines?

Ocular migraines were once thought to result primarily from changes in the brain’s blood vessels. Current understanding places greater emphasis on nerve-cell signaling and pain pathways.

“Ocular migraines are believed to be caused by ‘cortical spreading depression,’ which is a slow wave of electrical brain activity that affects the visual signaling pathways in the brain,” says Dr. Carroll.

Anyone can have an ocular migraine, but they are more common in people with a personal or family history of migraine and in women during times of hormonal change, such as menstruation, pregnancy and perimenopause.

Ocular Migraine Triggers

Triggers vary from person to person, and an episode does not always have an obvious cause.

“Triggers are the same as for migraine headaches,” says Dr. Carroll.

Common triggers include:

• Stress
• Poor or disrupted sleep
• Weather changes, especially heat exposure or becoming overheated
• Hormonal shifts
• Dehydration or skipped meals
• Bright or flickering screens and bright lights, including fluorescent lights and some LED headlights
• Certain foods and beverages, including alcohol, aged cheeses, processed meats, dark chocolate, caffeine and monosodium glutamate (MSG)

“Ocular migraines are often more directly linked to screen triggers than non-ocular migraines,” says Dr. Carroll.

How To Identify Your Migraine Triggers

Keeping a migraine diary can help identify patterns and triggers.

Track:

• When migraines occur, including date and time
• How long they last
• Whether they affect one or both eyes
• Screen exposure
• What you ate or drank beforehand
• Sleep quality
• Stress levels
• Hormonal changes

Difference Between an Ocular Migraine and Retinal Migraine

An ocular migraine typically affects both eyes and causes temporary visual disturbances. But a retinal migraine is a rare condition that affects only one eye and may cause temporary dimming, a blind spot or vision loss.

Because vision changes in only one eye can also be caused by conditions affecting the retina, optic nerve or blood flow to the eye, they should be evaluated promptly by a doctor.

When Should You See a Doctor?

Contact your doctor if visual symptoms are new, changing or becoming more frequent. While ocular migraines are often harmless, other eye and neurological conditions can cause similar symptoms.

When Are Visual Symptoms an Emergency?

Most ocular migraines develop gradually, with visual symptoms building over several minutes and resolving within one hour. Symptoms caused by a stroke, however, tend to occur suddenly and are often accompanied by other neurological symptoms.

“Stroke symptoms happen instantly and often have other associated neurologic deficits, such as weakness, imbalance or loss of sensation,” says Dr. Carroll.

Seek medical care immediately by calling 911 or going to the nearest emergency department if you experience any of the following:

• Sudden or complete vision loss
• Dizziness or vertigo accompanied by weakness, numbness, trouble speaking, confusion or loss of balance
• A sudden, severe headache unlike previous headaches
• Visual symptoms that last longer than 60 minutes

Sudden vision loss can also result from retinal detachment, reduced blood flow to the eye or another eye emergency.

Can Ocular Migraines Cause Permanent Vision Loss?

A typical visual aura is temporary and does not usually damage the eyes or cause lasting vision loss. Once an episode is over, your vision should return to normal.

While ocular migraines generally do not affect long-term vision, there is a small association between migraine with aura and stroke.

“Patients with ocular migraines are at a slightly increased risk for ischemic stroke. However, the overall absolute risk remains low in the absence of other stroke risk factors. Smoking and taking estrogen-containing birth control can increase the risk of stroke in patients with ocular migraine,” says Dr. Carroll.

Although the risk remains low for most people, it’s important to discuss your personal risk factors with your doctor.

How Are Frequent Ocular Migraines Treated?

“If ocular migraines are frequent, bothersome or disruptive to your daily activities, talk to your doctor about treatment options to reduce their frequency and severity, especially if they are associated with painful headaches,” says Dr. Carroll.

Treatment options include:

• Medication for migraine pain, such as anti-inflammatory medications
• Preventive medication to reduce the frequency of episodes, such as calcitonin gene-related peptide (CGRP) medications
• Identifying and avoiding triggers
• An eye exam or neurological evaluation if the diagnosis is unclear

Because visual aura cannot typically be stopped once it starts, treatment focuses on prevention.

Can You Prevent Ocular Migraines?

“Ocular migraines need to run their course once they start, so prevention is the goal,” says Dr. Carroll.

Consistent habits can reduce their frequency or severity:

• Maintain regular sleep and meal schedules.
• Stay hydrated throughout the day.
• Exercise regularly.
• Manage stress.
• Reduce glare and screen brightness and take frequent breaks from screens. (Follow the 20-20-20 rule: Every 20 minutes look 20 feet away from your screen for 20 seconds.)
• Limit known food or caffeine triggers.
• Avoid smoking.