Have you seen the study where they slowly degrade the quality of letters until a passage becomes illegible? The group on psilocybin is consistently able to derive the correct meaning from the text at levels the control group cannot.
Pupil dilation, literally allows more light to enter the eye and more signal to travel down the optical nerve.
In fact, serotonin (the primary neurotransmitter stimulated by most psychedelics) is heavily involved in perception and the internal processes by which we make up our realities.
Like, no, this doesn't prove any of the things people have extrapolated it into, but maybe think twice before saying there is no evidence to even suggest such a thing.