>>278560905
The pathway that affects the visual association cortex, which is the part of the brain that seems to be different in those with visual snow, may be quite complex. I don't know much about the biochemistry of acid so I can't provide any insight into the potential pathways, but it's not surprising a drug can have an effect there, and it aligns with the hypothesis that visual snow is caused by a failure in the brain's ability to do visual processing. 
An article here about visual snow: https://journals.lww.com/neurotodayonline/Fulltext/2019/01100/Visual_Snow_Is_a_Real_Neurological_Phenomenon.3.aspx