Visual Snow
Type: Persistent aura symptom — may last weeks, months, or years. Often bilateral (affecting both sides of vision or both ears). Rare but well-documented.
What is it?
Visual snow is a persistent visual disturbance where your entire field of vision appears covered with small moving particles, similar to TV static, grain, snow, or dots. It is present whether your eyes are open or closed and does not go away after the aura episode ends.
What it feels like
People describe visual snow as seeing constant, fine particles moving across their vision at all times. The snow does not clear or resolve; instead, it becomes a permanent layer over everything you see. Some describe it like looking through a screen of fine sand particles that drift continuously. Others compare it to television static or static from an old radio—a uniform field of tiny dots or lines of movement that never settle. The sensation can feel intrusive and exhausting, making it difficult to focus on details or read comfortably.
Patient artwork depicting visual snow / TV static — the continuous field of moving particles covering the entire visual field.
Patient artwork depicting visual snow, 2007.
How patients describe it
“With closed eyes, I may see ‘The Sandbox’ - this is a small patch of vision that resembles a field of sand particles drifting past my vision. They’re almost always moving, and they can drift in any direction either on their own, or I can ‘steer’ them.” — D.S.
“Whether you open your eyes or keep them shut. You haven’t experienced darkness for a long time. You always see more than there really is.” — K.O.
“Vision problem: I look at something, turn my head and then see it again… seeing something and then seeing it again. Or I am looking at something, move it and still see it where I moved it from.” — S.
What makes it worse
Visual snow may worsen during or after migraine attacks. Many patients report that visual stimuli—bright lights, high-contrast patterns, busy environments, screens—intensify the symptom. Stress, fatigue, and lack of sleep can make the snow more noticeable. Some report worsening during or around menstrual cycles.
What may help
Some patients report that dark glasses or blue light filters reduce the visual discomfort. Rest, particularly visual rest in dimmer environments, may provide relief. Stress reduction techniques, mindfulness, and distraction strategies help some people manage the symptom. Adequate hydration and sleep may help reduce severity. A few patients report modest improvement with cognitive behavioural therapy approaches.
Related symptoms
- Visual perseveration (afterimages and trails)
- Photophobia (light sensitivity)
- Visual loss or blurred vision
- Floaters and visual disturbances
Clinical note
Visual snow is the most common persistent aura symptom, reported by 51 of 60 subjects in clinical studies. Persistent visual snow should be evaluated by a neurologist to rule out stroke, hallucinogen persisting perception disorder (HPPD), or other conditions. A normal brain MRI is part of the diagnostic workup for persistent aura without infarction.
If this is the first time you experience these symptoms, or they feel different from previous episodes, seek medical evaluation to rule out other causes.