Sleep masks, when used for Cluster Headache management, work by creating total light occlusion which can help modulate the hypothalamic-sympathetic nervous system activity. By blocking light stimuli, they may interrupt potential photosensitive triggers and help regulate circadian rhythms that are often dysregulated in cluster headache pathophysiology. The primary physiological effect is reducing environmental visual stimulation and potentially mitigating neurogenic inflammatory responses associated with the headache syndrome.