Visual snow syndrome: a comparison between an Italian and British population

Abstract

Introduction Visual snow manifests as a pan‐field, dynamic visual disturbance described as continuous TV‐static‐like tiny flickering dots. Current diagnostic criteria further require at least two additional symptoms for the Visual Snow Syndrome (VSS) from: palinopsia (afterimages and trailing), entoptic phenomena (floaters, blue field entoptic phenomenon, photopsia, self‐light of the eye), photophobia and nyctalopia. Our objective was to compare the phenotype of VSS in an Italian and British population. Methods VSS patients were characterized clinically using the current criteria. An online survey was prepared in collaboration with the patient group Eye‐on‐Vision. Patients were directed to the site if they contacted us by email asking to be involved in research. Following data collection, we compared the phenotypic characteristics of a sub‐group of British versus Italian patients taking part in the survey. As we expected more responses from the UK, we matched one‐hundred UK patients for gender and age with our Italian cohort. Results Patients were enrolled from the UK (n = 100) and Italy (IT) (n = 100). The populations had similar demography. Following multiple correction testing there were no differences in VSS features between the two groups. The same was true for the prevalence of migraine and previous use of recreational drugs. Conclusion This is the first study comparing the phenotype of VSS between two distinct populations. Our findings suggest that the visual snow phenotype, as well as migraine comorbidity, are similar across the two groups.