The pupil size before application of the light stimuli was smaller after THC administration compared to the placebo group, hence indicating that against common belief THC much rather leads to miosis and not mydriasis, similar to other drugs such as opioids, neuroleptic drugs, cholinergic drugs like pilocarpine and acetyl-cholinesterase inhibitors like neostigmine and pyridostigmine that are known to cause miosis. Here, ACHE is linked to Miosis.