Visual snow syndrome (VSS) is associated with palinopsia, photophobia, photopsias, entoptic phenomena, nyctalopia and tinnitus and—in 60% of cases—migraine. However, many doctors still consider it merely a side effect of the migraine itself. Now, a research team out of Australia is hoping new data will change that perception.
“VSS is poorly recognized, not only in the neurological and ophthalmic communities, but also in the neuro-ophthalmic community,” reads their report, published recently in the Journal of Neuro-Ophthalmology. “It is often designated as being psychogenic, to the detriment of the patient.” Patients with VSS experience flickering dots occupying the entire visual field.
They’re hoping their comprehensive review of 105 articles culled from peer-reviewed academic literature will help shed some light on the subject.
According to their research, VSS is a syndrome independent of other conditions, such as migraine, and is likely associated with hyperactive visual cortices or, perhaps, impaired processing of simultaneous afferent information projecting to the cortex. “VSS likely results from widespread disturbance of sensory processing resulting in sensory misperception,” explain the investigators. They looked into the collected research documenting the clinical features of VSS, its pathophysiology and neurophysiological impact. “Neuroimaging studies in migraine and VSS have shown unique characteristics as well as overlap consistent with the observation of clinical overlap of these two disorders,” the article says, suggesting a clinically objective metric could help identify the boundaries between the two syndromes.
Additionally, the article offers several options for treatment for the condition it concludes is “due to impaired processing rather than structural pathology.” These therapies include colored lenses, lamotrigine (which blocks voltage-sensitive sodium channels) and acetazolamide.
|White O, Clough M, McKendrick A, Fielding J. Visual snow: visual misperception. J Neuro-Ophthalmol. August 7, 2018 [Epub ahead of print].|