Topic summary
Visual snow
Extracted from the Wikipedia article Visual snow syndrome.
Difference from visual snow
Visual snow—the symptom—may sometimes be a transient experience, and it is possible that it is a natural phenomenon, sometimes thought to be visible to many people if they focus on it. In visual snow syndrome, however, visual snow is ever-present, regardless of lighting conditions and even when the eyes are closed. In contrast to visual phenomena caused by migraines, which can last up to about an hour, static caused by visual snow syndrome lasts continuously for several months.