Näköpseudohallusinaatio

Näkösyönhäiriö, commonly referred to as visual snow syndrome, is a neurological condition characterized by a constant, persistent visual disturbance that resembles television static or "snow" superimposed on the entire visual field. This phenomenon is not a hallucination, as the individual is aware that the visual snow is an anomaly and not a real object or phenomenon.

The visual snow typically appears as tiny, flickering dots of white or gray that are present day and night. It can affect all areas of vision, including central and peripheral vision. Beyond the visual snow itself, individuals with visual snow syndrome often experience a constellation of other visual symptoms. These can include persistent afterimages, photophobia (sensitivity to light), nyctalopia (difficulty seeing in low light), and palinopsia (seeing lingering images of objects after they have moved or disappeared). Some individuals may also report a form of "visual static" in their hearing or a sensation of "buzzing" in their ears.

The exact cause of visual snow syndrome is not fully understood, but research suggests it may be related to abnormalities in the brain's visual processing centers, possibly involving the occipital lobe and its connectivity. It is often associated with other neurological conditions, such as migraines and certain types of epilepsy, although it can also occur in isolation. Diagnosis is typically based on a detailed medical history and a comprehensive eye examination, often supplemented by neurological assessments. There is currently no cure for visual snow syndrome, and treatment focuses on managing associated symptoms and improving the patient's quality of life. Strategies may include avoiding triggers like bright lights, using tinted lenses, and exploring certain medications that may help alleviate some of the associated visual disturbances.