Vinod Kumar MUGADA, Greshma Ratna Priyanka SARAGADAM, Sai Sowjanya BADITHABOYINA, Priyadarshini Reddy KOYYA, Srinivasa Rao YARAGUNTLA
Journal of Experimental and Clinical Medicine - 2026;43(1):88-95
Visual snow syndrome (VSS) is a chronic perceptual disorder defined by persistent pan-field visual static with >=2 additional symptoms, namely palinopsia, photophobia, nyctalopia, or enhanced entoptic phenomena, lasting >=3 months after exclusion of ophthalmic and structural neurological disease. Prevalence estimates range between 1.4-3.3% reported currently. Emerging evidence situates VSS along a rare-network spectrum characterized by thalamocortical dysrhythmia and cortical hyperexcitability, with convergent neuroimaging findings of hypermetabolism and altered connectivity in the lingual gyrus and motion area V5/MT, and microstructural white-matter changes linking visual and salience networks. Clinically, VSS frequently co-occurs with migraine and tinnitus, alongside anxiety and depression, amplifying disability. Differential diagnosis hinges on the disorder's continuous course and normal ophthalmic testing, distinguishing it from migraine aura, retinal dystrophies, epilepsy, and drug-induced phenomena. Therapeutic evidence remains heterogeneous and largely class IV: lamotrigine yields partial improvement in a subset; benzodiazepines, topiramate, and acetazolamide show inconsistent benefits; migraine-specific agents are generally ineffective. Non-pharmacological adjuncts such as precision chromatic filters (e.g., FL-41), mindfulness-based cognitive therapy, and neuro-optometric rehabilitation, can mitigate symptom burden or functional impact; early neuromodulation trials (rTMS) report mixed results. Standardized outcome measures integrating patient-reported and objective neurophysiological/neuroimaging markers are urgently needed, as are multi-centre-controlled trials to resolve response heterogeneity and delineate VSS-migraine-tinnitus interfaces. This integrative synthesis consolidates clinical features, mechanistic models, diagnostic touchpoints, and current management strategies to inform rare-disease care pathways and future targeted interventions.
