Learn About

Visual Snow Syndrome

Facts About the Condition


Visual Snow Syndrome (VSS), also known as Visual Snow (VS), is a neurological condition that has devastating effects on an individual’s vision, hearing, and cognitive functioning. Once thought to be rare, it is now estimated that 2-3% of the world’s population has symptoms of the condition. People from around the world of all ages and walks of life are and can be affected by it. Most often, the condition causes people to process visual information abnormally, making normal life more difficult for them. Patients see flashing lights, flickering dots, and static, all of which obstruct their visual field 24/7. There is no relief for them, even when their eyes are closed. What differentiates Visual Snow symptoms from other fleeting phenomena is that they are constant, not temporary, meaning that they do no go away on their own. The condition also has an array of non-visual symptoms (see below for more details).

The exact cause of Visual Snow is still unknown. However, research indicates there is a probable connection between hyperactivity in the visual cortex of the brain and the origin of this syndrome. Moreover, it is a neurological (brain-related) condition, not ophthalmological (related to the eyes). Visual Snow is a brain-processing issue that affects an individual’s eyesight, but it is unrelated to the structural integrity of the eyes.  

The diagnosis of Visual Snow Syndrome is typically difficult because although it affects the eyes, ophthalmologic/optometric examinations typically yield “normal” results. Neuro-ophthalmologists are typically more equipped to address this condition.

CLICK HERE to view the Diagnostic Criteria (to share with your doctor, etc.), as well a more comprehensive list of visual symptoms.

Visual Symptoms

  • Snow-like dots all over the field of vision
  • Small floating objects or flashes of light
  • Sensitivity to light (Photophobia)
  • Continuing to see an image after it is no longer in the field of vision (Palinopsia)
  • Seeing images within the eye itself (Entoptic phenomena)
  • Other visual effects such as starbursts, halos, and double vision (Diplopia)

Non-Visual Symptoms

  • Ringing, humming, or buzzing sounds (Tinnitus)
  • Feeling detached from yourself (Depersonalization)
  • Symptoms of anxiety and/or depression can sometimes develop as a result of having to deal with a constant medical condition like Visual Snow Syndrome
  • Muscular pain/headaches

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“Ten years ago, in 2012, we presented work at a neurology meeting systematically describing why Visual Snow was not simply migraine aura and was a distinct disease entity. This was not received with universal acclaim, to say the least. In the intervening period, visual snow has come in from the medical ‘cold’ and is being studied actively by a number of groups on three continents. The recognition of the condition, broadening education, and funding research would not have happened were it not for the Visual Snow Initiative. I realize to the many with this often very disabling condition that it seems nothing has or is being done. Progress to treatment is never fast enough nor advances to recognition and understanding. With that said, visual snow research would be idling in a backwater where it not the Initiative. Going forward, we need to double, re-double, and re-double again our efforts for the search for effective treatments and, one day, a cure. Thank you for the Visual Snow Initiative for all you have done and continue to do.”

— Peter Goadsby, MD, PhD, DSc, Professor of Neurology, UCLA, Awarded 2021 Brain Prize

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