Visual snow is a neurological condition characterized by the continuous perception of “visual static” or “visual noise". People with visual snow experience a grainy or flickering pattern in their visual field, often present even when looking at a blank or neutral background. It is constant, even when the eyes are closed. It can be associated with other symptoms including tinnitus, headaches and anxiety.
There are several types of visual snow. Here are a few types of visual snow that people might experience:
Classic Visual Snow: This is when everything you see looks like there’s static or little “dots” all over, kind of like the snow on a TV when it isn’t tuned to a channel.
Colorful Visual Snow: Some people see the static as bright colors, like rainbow-like dots or flashes, instead of just black-and-white.
Afterimages: This happens when you see “ghost” images or shadows after looking at something, like when you look at a bright light and still see a light spot for a little while.
Nighttime Snow: This is when the static gets worse in the dark, making it hard to see clearly at night.
The cause of visual snow is not fully understood. It is believed to arise from dysfunction in the way the brain processes visual information. It is typically thought to involve abnormal activity in the visual processing pathways.Several possible mechanisms may contribute to the condition:
Cortical Hyperexcitability: This refers to an increased level of spontaneous electrical activity in the brain’s visual processing regions. This heightened excitability can lead to the perception of “visual noise” or static, even in the absence of external visual stimuli.
Impaired Visual Perception Pathways: Visual snow may be linked to disruptions in the way the brain processes and integrates information from the eyes. This includes abnormalities in the retino-geniculate-striate pathway, where information is relayed from the retina to the brain.
Neurotransmitter Imbalance: There is some evidence suggesting that imbalances in neurotransmitters, such as serotonin or glutamate, may play a role in the development of visual snow. These neurotransmitters are involved in regulating neural excitability and sensory processing.
Migraine Mechanisms: Visual snow is commonly associated with migraine sufferers, suggesting a shared pathophysiological mechanism. Migraines are thought to involve cortical spreading depression (CSD), a wave of neuronal depolarization that spreads across the cortex, which may contribute to visual disturbances like visual snow.
Thalamic Dysfunction: The thalamus is a key relay station in the brain for sensory information. Dysfunction in thalamic processing could lead to misinterpretations of visual input, resulting in the perception of persistent visual noise.
Other Factors: Visual snow may also be associated with other conditions, including anxiety, depression, fibromyalgia or visual processing disorders. It may also be triggered or worsened by factors such as stress, lack of sleep, or drug use.
The outcome of visual snow can vary significantly from person to person, as the severity and impact of the condition depend on multiple factors, such as the intensity of symptoms, the presence of other associated conditions, and how effectively the symptoms are managed.Visual snow is typically a chronic condition, meaning it often persists over time, with symptoms that can last for years or even a lifetime. Some people experience a mild version of visual snow that does not significantly interfere with daily life, while others may have more severe symptoms that affect vision, concentration, or quality of life.The intensity of visual snow symptoms can fluctuate. Some individuals may notice their symptoms worsen during stress, lack of sleep, or after exposure to bright lights or certain triggers. Others may experience periods of relative relief or symptom reduction, though the condition rarely completely resolves on its own without treatment.
For some, visual snow can have a significant impact on daily functioning, particularly when combined with other symptoms like migraines, tinnitus or light sensitivity. Tasks that require visual precision, such as reading or driving, may become challenging. People with visual snow often report difficulties with concentration or cognitive overload due to the constant presence of visual “noise.”
Over time, many individuals with visual snow may adapt to the condition, learning to cope with or minimize its effects. Some may become more accustomed to the visual disturbances, while others may develop strategies to manage related symptoms, such as avoiding triggers, using tinted glasses to reduce light sensitivity, or making lifestyle adjustments like improving sleep or managing stress.
While there is currently no cure for visual snow. There are medications that have bee used to reduce the intensity of the symptoms, such as those used for migraines including lamotrigine, Nortriptyline, propranolol and verapamil.
Cognitive behavioral therapy (CBT) and relaxation techniques may also help in some cases.