Visual snow is considered a disorder of central visual processing resulting in a perturbed perception of constant bilateral whole-visual field flickering or pixelation. When associated with additional visual symptoms, it is referred to as visual snow syndrome. Its pathophysiology remains elusive.
A retrospective study now provides Class IV evidence for a possible benefit of lamotrigine in a minority of patients.
Major challenges remain the subjective nature of the disease, its overlap with migraine, and the lack of quantifiable outcome measures, which are necessary for clinical trials. In that context, refined perceptual assessment, objective electrophysiological parameters, as well as advanced functional brain imaging studies, are promising tools in the pipeline.