Around 25% to 30% of migraineurs experience visual aura symptoms. It can be challenging to decide whether the visual disturbance is due to a migraine or is a symptom of a more severe problem. However, most migraine-related symptoms are seen in both eyes, although the aura may occur in one side of the visual field. 

Covering one eye can help discern whether the aura affects just one eye. If the symptoms remain even when the eyes are closed, it signals a brain issue. Also, if you have complete loss of vision on one side, you may be experiencing something due to a disruption in your brain.

What are visual disturbances and auras? Who experiences them and why? Many who have visual disturbances have common symptoms and common triggers. 

An Overview of Visual Disturbances

A visual disturbance is when an individual experiences flashing or shimmering light in their field of vision. Typically, the disruption lasts around 20 to 30 minutes, often without headache. Migraineurs who also have visual auras only see them for a short time, anywhere from a few seconds to a half-hour, either before or during a migraine.

People who suffer migraines may suddenly develop visual disturbances where they had not experienced any before. Often, the problem is a function of aging. The severity of the migraine may diminish, but the patient starts seeing auras instead. Some patients may not experience a visual aura until they are older than 50.

Visual disturbances during typical migraines should not be confused with retinal or ocular migraines, where the individual may have partial or total loss of vision in one eye along with a headache.

Visual disturbances are most commonly found in:

• Women 
• Individuals under 40
• Individual over 60
• Patients with a personal or family history of migraines

Up to 70% of those with ocular or retinal migraines have a family history of the condition. 

People with the following conditions also have a higher risk for visual disturbances:

• Brain tumors
• Cataracts 
• Glaucoma 
• Diabetes 
• Macular degeneration
• Migraines 

Finding out what causes the disturbance becomes critical as many of the listed conditions are serious.

Types of Visual Disturbance

Visual disturbances can be scary but are often short-lived. If one occurs when driving or operating heavy machinery, stop and wait for the symptoms to recede. If they happen more than once, you should note when, where, and what type of disturbance you experience and bring the diary to your healthcare provider to assist with diagnosis.

Diplopia

Diplopia is a fancy name for double-vision, which can be a symptom of severe health problems. If you begin to experience diplopia, see your healthcare provider immediately.

Diplopia can be in one or both eyes. When it affects one eye, it’s called monocular diplopia. It only occurs when the affected eye is open. It may result from physical changes to the lens of the eye, the cornea, or the retinal surface. 

Blindness 

A person can experience partial or total blindness. With partial blindness, someone can still see light and some of their surrounding environment. In total blindness, the loss of vision is complete. People with 20/200 vision are considered legally blind.

Blindness can be caused by aging, psychological disorders, exposure to chemicals, macular degeneration, optic neuritis, Parkinson’s disease, sickle cell anemia, and some medications. 

Blurred Vision and Halos

Blurred vision is often how people experience visual auras with migraines. It can occur when your eyesight changes over time or because of another condition. Corrective lenses can fix eyesight changes, but other treatment might be needed if the blurred vision is due to something else. 

A halo is the appearance of a circle of light around objects. 

Blurred vision and halos are found in macular degeneration, cataracts, corneal abrasions, glaucoma, optic nerve problems, eye injuries, tumors, and strokes. Treating the underlying condition often eliminates the vision issue.

What Are Ocular Migraines?

An ocular migraine is a rare condition characterized by temporary vision loss in one eye. Usually, it begins as a small central blind spot called a scotoma affecting ventral vision. It can expand to impact the entire visual field of one eye.

The patient may also see scintillations (flickering lights) or metamorphopsia (zigzag lines) inside the blind spot. The term ocular migraine is often misused to describe a less serious condition like visual migraine or migraine aura.

Common Visual Disturbances

In migraines, visual symptoms are positive, negative, or altered. 

• Positive disturbances make you see something that isn’t there.
• Negative disturbances mean part of your vision is missing.
• Altered or distorted vision means you feel like you are looking through water or heat waves or have blurred vision. Your vision may seem fractured or cracked in a mosaic or kaleidoscope effect. Sometimes objects seem larger, smaller, or closer together than they are. You may lose color vision.

You may see flashes of light (scintillations) that start in the periphery of your vision and expand to become more central. The light may be black, white, or brightly colored. Often, people describe it as a zigzagging pattern or having the appearance of shards of broken glass. 

The individual often has a problem whether the eyes are open or closed. It usually affects both eyes, and it can last 20 to 30 minutes. If you ever experience partial or total vision loss or persistent flashing, see your optometrist or primary care provider, especially if it's the first time.

Common Triggers

Like migraines, visual disturbances can be triggered. Common triggers include:

• Stress or fatigue
• Flashing or flickering lights
• Glare from a window, monitor, of paper
• Exercise or bending over
• Dehydration 
• Some foods like chocolate, aged cheese, or alcohol
• Excessive heat

When to Be Concerned

You may need an emergency room or a healthcare provider if you have any of the following symptoms—many signal potential retinal or vitreous detachment.

• New dark spots or floaters in one eye that don’t go away
• New flashes of light in one eye that don’t go away within an hour
• Episodes of transient vision loss in one eye could signal stroke or arterial inflammation
• Tunnel vision, loss of one side of the visual field, or an episode of total blindness without headache may be a stroke or a series of small strokes. Visual problems are often accompanied by dizziness, imbalance, numbness, or weakness, and possibly head pain.
• A previously stable pattern of migraine visual symptoms changes drastically or increases in duration.

Keep a diary of your visual disturbances, including when they occurred and what you were doing. It helps diagnosis immensely.

Treatment

There aren’t a lot of treatments for visual disturbances outside of corrective lenses. However, if you have an underlying condition, treating it often relieves the vision problems. Dietary changes to better manage conditions like diabetes can also help.

If corrective lenses don’t work and there is no other problem, surgery might relieve or repair damaged nerves and muscles that cause the disturbance.

Are you experiencing visual disturbances? Contact your optometrist, neurologist, or primary care physician. If you want to know more, please contact the Migraine Relief Center.