title: Visual snow: A thalamocortical dysrhythmia of the visual pathway?
abstract: In this paper we review the visual snow (VS) characteristics of a case cohort of 32 patients. History of symptoms and associated co-morbidities, ophthalmic examination, previous investigations and the results of intuitive colourimetry were collected and reviewed. VS symptoms follow a stereotypical description and are strongly associated with palinopsia, migraine and tinnitus, but also tremor. The condition is a chronic one and often results in misdiagnosis with psychiatric disorders or malingering. Colour filters, particularly in the yellow-blue colour spectrum, subjectively reduced symptoms of VS. There is neurobiological evidence for the syndrome of VS that links it with other disorders of visual and sensory processing such as migraine and tinnitus. Colour filters in the blue-yellow spectrum may alter the koniocellular pathway processing, which has a regulatory effect on background electroencephalographic rhythms, and may add weight to the hypothesis that VS is a thalamocortical dysrhythmia of the visual pathway.
authors.affiliation: Save Sight Institute, University of Sydney, 8 Macquarie Street, Sydney, NSW 2000, Australia; Department of Ophthalmology, Prince of Wales Hospital, High Street, Randwick, NSW, Australia.
authors.forename: Jenny L
authors.initials: JL
authors.lastname: Lauschke
authors.affiliation: Department of Neuro-Ophthalmology, Moorfields Eye Hospital, London, United Kingdom.
authors.forename: Gordon T
authors.initials: GT
authors.lastname: Plant
authors.affiliation: Save Sight Institute, University of Sydney, 8 Macquarie Street, Sydney, NSW 2000, Australia. Electronic address: clare.fraser@sydney.edu.au.
authors.forename: Clare L
authors.initials: CL
authors.lastname: Fraser
mesh_terms: D000293:Adolescent; D000328:Adult; D002540:Cerebral Cortex / Q000503:physiopathology; D055253:Color Vision; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008881:Migraine Disorders / Q000175:diagnosis*; D013577:Syndrome; D013788:Thalamus / Q000503:physiopathology; D014012:Tinnitus / Q000175:diagnosis; D014202:Tremor / Q000175:diagnosis; D014786:Vision Disorders / Q000175:diagnosis*; D014795:Visual Pathways / Q000503:physiopathology*
keywords: Colour filter; Migraine; Palinopsia; Positive persistent visual disturbance; Thalamocortical dysrhythmia; Visual snow