"Magic" mushrooms may have helped a guy with color blindness differentiate between red and green better, according to a case report by doctors and researchers from the Cleveland Clinic in Ohio and the University of Alabama, Birmingham. A 35-year-old man with mild deuteranomalia, a type of red-green blindness, experienced "modest, long-lasting improvements" in his red-green color vision after a single dose of psilocybin-containing mushrooms. This is the first published experimental data or case report on this potential benefit of psilocybin, and, according to the report's authors, is considered anecdotal. So, more research is needed to know for sure how it works and if it could help others too.
[The man] had periodically taken a variety of psychedelics over the years, including psilocybin, LSD, and DMT. After some of these sessions, he noticed an improvement in his red-green vision, which eventually inspired him to conduct his own experiment.
Just before he ingested a single dose of dried psilocybin mushrooms, the man took the Ishihara test, a common measure of red-green blindness. Then he kept taking the test at regular intervals for the next four months, reportedly only checking the answers at the end of the experiment. At some point, he talked about his experiment with the doctors, who then administered their own test 436 days after his initial psilocybin use.
The Ishihara test measures red-green color vision using colored dot plates. A normal score is 17 or higher on plates 1-21. Before taking magic mushrooms, the man scored 14. Six hours after, he scored 15, then 18 a day later, and peaked at 19 eight days later. Over a year later, he scored 16, but had used other psychedelics in the meantime. The improvement lasted at least 16 days, but it's unclear if the initial psilocybin dose caused ongoing effects. The man's color blindness likely comes from genetic mutations in retina cells, which psilocybin can't fix. Instead, it might improve the brain's processing of limited visual input, as psychedelic users often report vivid color alterations.