National Center for Advancing and Translational Sciences Genetic and Rare Diseases Information Center, a program of the National Center for Advancing and Translational Sciences

Visual snow syndrome

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Other Names:
Visual snow
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Visual snow syndrome causes a person to see numerous flickering tiny dots that fill the entire visual field in both eyes. People describe it as being similar to "snow or static" as used to be common in older television.[1] Other symptoms may include migraines, drifting blobs of varying size and shape (floaters), or other visual effects such as glare, halos, starbursts, odd colors and shapes, or double vision (diplopia).[1][2] 

The cause of visual snow syndrome is unknown, but likely involves abnormal processing of visual information.[1] Visual snow syndrome is diagnosed primarily by symptoms that last for more than three months despite normal eye examinations and ruling out other possible causes. There is no evidence-based treatment for visual snow at this time, but some people have been reported to be helped by medications used to prevent migraines, antidepressants, anti-seizure medication, or over-the-counter pain medications.[1][2]
Last updated: 3/6/2018
The primary sign of visual snow syndrome is seeing snow-like dots all over the visual field. For most people with the syndrome, the visual snow is always present and occurs in both eyes. The visual snow may worsen at times when the brain and eyes are "tired", such as after looking at a computer screen for a long time or during times of stress.[1] Other visual symptoms that can be associated with visual snow syndrome include sensitivity to light (photophobia), continuing to see an image after it is no longer in the field of vision (palinopsia), impaired night vision (nyctalopia), and seeing images from within the eye itself (entoptic phenomena), such as seeing small floating objects or flashes of light.[1][2]

Visual snow syndrome may also be associated with other symptoms including migraines, ringing in the ears (tinnitus), tremors, balance problems caused by feeling like a person's surroundings are spinning (vertigo), and fatigue.[1][2][3] Some people with visual snow syndrome say they feel detached from themselves or from the world around them (depersonalization).[3] Some people with visual snow syndrome also suffer from anxiety and depression.[4] 

Symptoms of visual snow syndrome can begin at any time of life but most frequently begins in young adulthood.[1]
Last updated: 3/6/2018
The cause of visual snow syndrome is unknown.[2][5] Some authors have suggested the symptoms are caused by a defect or disorder in the visual pathway or within the eyes themselves. This seems unlikely, however, since problems with the eyes typically are not identified during eye examinations.[2][5] Other authors believe the symptoms are caused by a defect or disorder of the brain (a neurological disorder).[5][6] It has been proposed that the syndrome may involve dysfunction of visual processing in a structure in the brain called the lingual gyrus, in which there is abnormally increased activity (hypermetabolism).[2][6][7] Other possible causes include visual cortical hyperexcitability (abnormally increased activation of neurons in the cerebral cortex) and thalamocortical dysrhythmia (an imbalance or loss of equilibrium between the brain's thalamus and cerebral cortex).[1][2][6][8]
Last updated: 11/30/2018
Visual snow syndrome is not known to be caused by changes (mutations or pathogenic variants) in any one gene. It is possible that visual snow syndrome is caused by a combination of environmental and genetic factors. About 10% of people who have visual snow syndrome have other family members with the syndrome as well.[1] This suggests that there may be some genetic factors that make it more likely for a person to have visual snow syndrome, but the exact genetic factors are not well-understood.
Last updated: 3/6/2018
Visual snow syndrome is suspected when a doctor observes signs such as a person seeing visual snow that never goes away. A diagnosis of visual snow syndrome can be confirmed if the symptoms have lasted longer than three months and the person has two of the following additional symptoms:[1]
In order for a person to be diagnosed with visual snow syndrome, other potential causes of the symptoms such as migraine visual aura must be ruled out. Most people with visual snow syndrome have normal vision tests and normal brain images.[1]
Last updated: 3/6/2018
Unfortunately, there is no known cure for visual snow syndrome. However, medications may reduce symptoms of the syndrome for some people. At this point, treatment options are based on what has been reported as being effective in single case reports or a small number of people. No one treatment is known to work for everyone with visual snow syndrome, and no studies have been completed testing the effectiveness and safety of the treatments.[1][2] Therefore, it is very important that a person with visual snow syndrome talks to their doctor about the benefits and risks of any treatment.

Medications that may be prescribed include:[1][2] 
Using tinted contact lenses (colorimetric lenses) may help some people with the syndrome.[1][8]

Because visual snow syndrome can be associated with anxiety or depression, it is important to speak with a doctor about proper treatments for these symptoms.[2][4]
Last updated: 3/6/2018
Because the symptoms are always present, visual snow syndrome can decrease a person's quality of life. While some people are able to adjust to the symptoms, others find the symptoms very disabling. The symptoms of visual snow syndrome can change over time, with some people noticing an improvement of symptoms (with or without treatment) and some people noticing that their symptoms worsen.[3]

Treatment typically does not completely relieve the symptoms of visual snow syndrome. However, many find even a lessening of the symptoms can greatly increase their quality of life.[1]
Last updated: 3/6/2018

Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.

Organizations Providing General Support

These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

Where to Start

  • The Eye on Vision Foundation is a non-profit organization that covers Visual snow syndrome and has information on the condition.
  • The National Organization for Rare Disorders (NORD) has a report for patients and families about this condition. NORD is a patient advocacy organization for individuals with rare diseases and the organizations that serve them.

In-Depth Information

  • Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
  • PubMed is a searchable database of medical literature and lists journal articles that discuss Visual snow syndrome. Click on the link to view a sample search on this topic.

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  1. Ghannam AB, Pelak VS. Visual Snow: a Potential Cortical Hyperexcitability Syndrome. Curr Treat Options Neurol. March, 2017; 19(3):9. https://www.ncbi.nlm.nih.gov/pubmed/28349350.
  2. Puledda F, Schankin C, Digre K, Goadsby PJ. Visual snow syndrome: what we know so far. Curr Opin Neurol. February 2018; 31(1):52-58. https://www.ncbi.nlm.nih.gov/pubmed/29140814.
  3. Visual Snow. Eye on Vision Foundation. http://eyeonvision.org/visual-snow.html.
  4. Schankin CG, Maniyar FH, Digre KB, and Goadsby PJ. 'Visual snow' - a disorder distinct from persistent migraine aura. Brain. May 2014; 137 (Pt 5):1419-1428. https://www.ncbi.nlm.nih.gov/pubmed/24645145.
  5. Metzler AI, Robertson CE. Visual Snow Syndrome: Proposed Criteria, Clinical Implications, and Pathophysiology. Curr Neurol Neurosci Rep. June 22, 2018; 18(8):52. https://www.ncbi.nlm.nih.gov/pubmed/29934719.
  6. Visual Snow Syndrome. National Organization for Rare Disorders (NORD). 2018; https://rarediseases.org/rare-diseases/visual-snow-syndrome/.
  7. Schankin CJ, Maniyar FH, Sprenger T, Chou DE, Eller M, Goadsby PJ. The relation between migraine, typical migraine aura and "visual snow". Headache. April, 2015; 55(4):592. https://www.ncbi.nlm.nih.gov/pubmed/24816400.
  8. Lauschke JL, Plant GT, and Fraser CL. Visual snow: A thalamocortical dysrhythmia of the visual pathway?. Journal of Clinical Neuroscience. June 2016; 28:123-127. https://www.ncbi.nlm.nih.gov/pubmed/26791474.