What Is Visual Snow Syndrome?

The main symptom of visual snow syndrome is visual snow, the persistent flickering of dots across your entire visual field, resembling television static. Visual snow is usually black and white but can be:

• colored
• flashing
• transparent

Up to 75% of people with visual snow syndrome also report at least three of the following symptoms:

• palinopsia, or seeing an after-image of objects after they’re gone
• light sensitivity
• impaired night vision
• enhanced entoptic phenomena, or visual changes originating from within the eye that might cause:
  • floaters in both eyes
  • blue field entoptic phenomenon, seeing squiggly lines when looking into bright blue areas like the sky
  • self-light of the eye, colored waves or clouds when eyes are closed in a dark space
  • spontaneous photopsia, bright flashes of light

The cause of visual snow syndrome is still largely unknown. Experts think it may be a neurological disorder of the brain’s visual processing center.

In particular, dysfunction and excessive activity of neurons in two parts of the brain may play a role:

• the primary visual cortex, which processes visual information
• the lingual gyrus, which plays a role in editing visual information for your brain to interpret

The exact area of brain involvement might vary slightly between people. This may also explain why people experience different symptoms.

In early studies, researchers found people with visual snow syndrome generally had typical scores on eye exams. People are usually young when they develop visual snow syndrome. It often seems to develop in childhood.

Some people develop visual snow syndrome after

• taking medications
• brain trauma
• infection

Much of what’s known about the causes of visual snow syndrome is limited to individual case studies. For example:

• A 2021 case study documented the first case of visual snow syndrome developing after COVID-19 infection.
• In a 2022 case study, researchers presented a case of visual snow syndrome developing after LASIK surgery.
• Another 2022 case study reported visual snow syndrome in a person who experienced a series of mild concussions.
• Another 2022 case study reported probable visual snow syndrome related to methylphenidate to treat a child with attention deficit hyperactivity disorder (ADHD).

In a 2020 study of a group of 1,100 people with visual snow syndrome, the average age was 29. About 40% of people in the study had symptoms for “as long as they could remember.”

The researchers found no difference in how common visual snow syndrome was among the sexes. But those who identified as female had more severe cases.

Visual snow syndrome appears to be highly related to migraine. This suggests that there might be a possible shared mechanism. Nearly 75% of people with visual snow syndrome have a history of migraine.

About 25% of people with visual snow syndrome have severe depression or anxiety.

Visual snow syndrome isn’t well recognized and is often misdiagnosed as persistent migraine aura.

Tests used to diagnose visual snow syndrome can include:

• physical exam
• eye exam
• neurological exam

To diagnose you with visual snow syndrome, a doctor would need to decide that you meet the following criteria:

• visual snow lasting longer than 3 months
• at least one of the following four additional symptoms:
  • palinopsia
  • enhanced entoptic phenomena
  • impaired night vision
  • light sensitivity
• symptoms not consistent with migraine visual aura
• symptoms that are not a more likely sign of another disorder or caused by psychotropic drugs

A doctor would also need to exclude any conditions that cause similar symptoms.

No current treatment has proven effective for treating visual snow syndrome. Researchers are continuing to investigate potential options.

Current evidence suggests the medications that prevent migraine, such as antidepressants or pain medications, don’t consistently improve or worsen visual snow syndrome. One single case study found potential benefits with the drug lamotrigine.

Recreational drugs and alcohol can worsen symptoms, at least temporarily.

Transcranial magnetic stimulation (TMS) is under investigation as a potential treatment. Some research suggests it may be beneficial, but larger studies are needed to fully explore its use. TMS uses magnetic fields to stimulate neurons in your brain.

There is interest in the use of tinted lenses to improve symptoms of visual snow syndrome.

Here are some frequently asked questions people have about visual snow syndrome.

Can visual snow syndrome cause blindness?

Visual snow syndrome isn’t usually progressive and does not lead to permanent blindness.

Some conditions that cause similar symptoms can cause vision loss. You’ll need a proper evaluation to rule these out.

Can I drive with visual snow syndrome?

The level of visual impairment varies significantly among people with visual snow syndrome. Many people can continue to drive if visual snow isn’t impairing their ability to see.

But people with severe symptoms or impaired night vision may not be able to drive safely or legally.

Does visual snow syndrome go away?

Visual snow syndrome is unlikely to go away by itself. As of now, there’s no cure, but a doctor can help you manage your symptoms.

How common is visual snow syndrome?

It’s not clear how common visual snow syndrome is. One study estimated that about 2% of people in the United Kingdom might have it.

But the people in the study were self-recruited, so there’s a good chance that this estimate is too high.

Visual snow syndrome is a neurological condition in which persistent dots appear in your visual field, resembling television static.

Researchers don’t know exactly what causes it, but they think that problems in the visual processing centers of your brain may play a role.

As of now, there’s no cure for visual snow syndrome. Still, a proper evaluation is important to rule out other conditions that can cause permanent vision loss.

Researchers continue to explore new treatment options.