Visual snow in hallucinogen-persisting perception disorder.
This article presents the case of a 24-year-old female patient who was referred to this department due to permanent flickering in front of both eyes. This flickering, described as being like visual snow in television, had started 1.5 years ago and was perceived to be very disturbing. Visual acuity, visual field and morphology of the anterior and posterior segment were bilaterally inconspicuous. A neurological examination including a magnetic resonance imaging of the cranium (cMRI) and visual evoked potentials (pattern-VEP) also showed no abnormalities. Furthermore, the patient suffered from schizophrenia. This also first occurred 1.5 years ago directly after consumption of a narcotic cocktail consisting of amphetamines, hallucinogens and alcohol. In a synopsis of the findings the patient was diagnosed with type II hallucinogen-persisting perception disorder. Treatment options for this disease are limited and the symptoms often remain permanently.