What Is Visual Snow Syndrome?

Visual snow syndrome is a disorder where people see tiny, flickering dots in their entire visual field. The syndrome was once thought to be a form of migraine, but research suggests it is a distinct medical condition related to one's visual processing.

There's no specific test for visual snow syndrome; it's usually diagnosed based on symptoms and ruling out other conditions. Anti-seizure medications are the current best treatment option, but they're not especially effective.

Visual snow syndrome is a fairly new diagnosis. No one knows how many people have it, although some researchers believe that up to 2.2% of the population may be affected in some way.

This article looks at visual snow syndrome and its symptoms, causes, and diagnosis. It also discusses possible treatment.

Signs and Symptoms of Visual Snow

Most people with visual snow syndrome see tiny dots across their visual field, even though they otherwise have no changes in their ability to see. The dots may get worse after looking at a screen for a long time or during times of high stress.

These dots can be described as "snow" or "static." They look similar to what you might see when watching an old television. They are usually black and white, though they can also sometimes be flashing, colored, or even transparent.

Some studies suggest that these symptoms appear to occur across a spectrum of visual snow disorders, implying potential differences in what a visual snow diagnosis means.

Visual Symptoms

The snow in your visual field isn't the only symptom of this condition. Other disabling visual symptoms can occur, such as:

• Floaters, the small shapes you may see in your visual field
• Photopsia, the starbursts or flashes of light that may suggest a health issue
• Nyctalopia, or impaired night vision
• Kaleidoscope vision, the color swirls often seen with migraines
• Palinopsia, or seeing something that isn't there anymore
• Photophobia, a heightened or unusual light sensitivity

Non-Visual Symptoms

With visual snow syndrome, there may be other symptoms besides what you see. Symptoms that aren't visual include:

• Migraines, a disabling headache often linked to visual migraine aura symptoms
• Tinnitus, or ringing in the ears
• Vertigo, a sense of spinning or dizziness, or balance loss
• Fatigue, an unusual exhaustion often related to another health issue
• Tremors, an uncontrollable motion in your body, often the hands
• Anxiety, a mild to severe response to stress
• Depression, a mood disorder associated with feelings of sadness and fatigue

Migraine is a symptom worth noting. A 2014 study of 120 patients with visual snow found that 70 of them also had migraines. Of those, 37 also had typical migraine auras. People who have migraine with aura see flashes of light or color when they have a migraine.

Having migraines made some symptoms of visual snow syndrome worse. In particular:

• Seeing an image when it isn't there anymore
• Light sensitivity
• Impaired night vision
• Spontaneous flashes of light
• Tinnitus

Many people with visual snow syndrome have migraines with or without aura, but the syndrome itself is not a migraine.

What Are the Causes of Visual Snow Syndrome?

Scientists don't know for sure what causes visual snow syndrome. It appears to be a complex neurological disorder.

Studies have shown that people with this syndrome have a brain abnormality in their lingual gyrus. This is a structure in the occipital lobe, which is located in the back of the brain. Because visual pathways meet in the occipital lobe, experts think an abnormality in vision processing might cause visual snow syndrome.

The nerve cells in the brains of people with visual snow syndrome may be too responsive to visual stimuli. These very sensitive nerve cells mistakenly send signals to the brain. The brain interprets them as real images.

In addition, scientists believe there may be a link between visual snow syndrome and certain conditions such as anxiety, depression, ADHD, and fibromyalgia.

Visual snow is also associated with brain damage caused by traumatic brain injury, and it may occur alongside other post-injury symptoms like headache. This may happen immediately or up to two to 12 weeks after a head injury.

How Is Visual Snow Syndrome Diagnosed?

To make this diagnosis, your healthcare provider will:

• Take a health history
• Complete a physical examination
• Refer you for an eye exam
• Conduct a neurological exam

Before diagnosing visual snow syndrome, other medical conditions need to be ruled out. The diagnosis will be made if you have seen "snow" or "static" consistently for longer than three months and have two or more of the following symptoms:

• Sensitivity to light
• Impaired night vision
• Seeing something when it is no longer there
• Other visual changes, such as seeing floating objects

A History of Misdiagnosis

In the past, people with visual snow syndrome were often misdiagnosed. Common misdiagnoses included:

• Migraine
• Psychogenic disorder, which means the symptoms have a psychological root
• Post-hallucinogenic drug use flashback

Most people with visual snow syndrome, however, have no history of drug abuse. Their symptoms also don't get better with standard migraine treatment.

Today, healthcare providers know more about visual snow syndrome and are better at spotting it. If you think you have the condition but were diagnosed with something else, consider getting a second opinion.

Visual Snow Treatment

Healthcare providers are still learning more about how to treat visual snow syndrome. If it's caused by an underlying condition, such as a concussion, then treatment of the underlying condition is needed.

For now, though, the primary focus is on treating symptoms, since the disorder does not appear to progress, or get worse, over time. Medications do not appear to be especially effective, however.

A literature review of 44 different drugs used to treat visual snow syndrome found that only eight worked even once. Lamotrigine, an anti-seizure medication, appeared to be the most helpful but reduced symptoms in only 22% of the cases in which it was used. Topiramate also seemed to offer some relief but only in 15.4% of cases.

Repetitive transcranial magnetic stimulation (TMS), a technique used in some Alzheimer's and migraine patients, uses magnetic pulses applied to the brain. It's also been studied in people with visual snow syndrome, but with conflicting results.

In some cases, people with visual snow syndrome say they've experienced relief when treated with tinted lenses in the blue-yellow light spectrum, but there's little data to support these effects yet.

Summary

Visual snow syndrome is uncommon. People with this syndrome see small dots like snow or static in their field of vision. Researchers think the syndrome may be caused by an abnormality in part of the brain. 

In the past, people with this syndrome were often misdiagnosed with migraines or other disorders. If you think you've been misdiagnosed, get a second opinion.

Healthcare providers don't yet know how to treat visual snow syndrome. Anti-seizure medication and antidepressants have worked for some patients. However, more research is needed.

A Word From Verywell

See your healthcare provider if you think you might have visual snow syndrome. Scientists now know that this syndrome is linked to a certain part of the brain. This will hopefully spur research into how to best treat this very real but rare condition.