Aceclidine is a parasympathomimetic agent used in the treatment of open-angle glaucoma as topical eye drop solution. It is as a muscarinic acetylcholine receptor agonist with weak anticholinesterase activity. Acting directly on the motor end-plate (cholinergic nerve endings) it decreases intraocular pressure and mediates the contraction of iris muscle. Aceclidine increased outflow facility in human eyes in vitro by a direct stimulation of the outflow tissues in the absence of an intact ciliary muscle. This effect was biphasic, occurring at concentrations of 10 uM and lower with no effect at higher concentrations. Passed numerous clinical trials in Russia, France, Italy and other countries and was widely used in Europe but never been in clinical use in USA.