There is no evidence showing that visual snow is associated with sinus pressure. Visual snow is usually caused by persistent migraine aura without infarction, which is a migraine complication. Optic neuritis (inflammation of the optic nerve) that caused by multiple sclerosis can also lead to snow vision. In some cases, people with illness such as lyme disease and auto-immune disease or noxious problems such as dehydration and over-acidification also claim that they have visual snow. But there is no scientific study supporting the relevance between visual snow and those diseases and conditions. Hallucinogen persisting perception disorder (HPPD) due to the use of hallucinogenic psychedelic drugs can lead to visual snow. Unfortunately, there is no established treatment for visual snow. However, if the visual snow is caused by HPPD, clonazepam and drug abstinence are helpful. For the case of persistent aura without infarction, acetazolamide is reported to be effective.