Serotonin levels are intimately linked with the musculature surrounding the eyes, short-sightedness and long-sightedness.
On Christmas Day last year I gave my mother MDMA, primed with a small amount of a MAOI. Halfway through the day she realised that she didn’t need her glasses to read. She had two reasonable high separate doses. Normally, even with her glasses on, she needs to hold reading material far away from her eyes. It was a massive correction in her eyesight that disappeared in the following days.
I am slightly short-sighted due to excessive reading but had unusually good long-range vision when I was a child. I have been resisting getting glasses for a few years because I’ve noticed that after yoga or working outside with plants my vision largely corrects itself. This MDMA/optometry issue needs to be studied.