<p>Pilocarpine Hydrochloride directly stimulates cholinergic receptors. It produces contraction of the iris sphincter muscle, resulting in pupillary constriction (miosis); constriction of the ciliary muscle, resulting in increased accommodation; and reduction in intraocular pressure associated with an increase in the outflow and a decrease in the inflow of aqueous humor. In chronic open angle glaucoma, the exact mechanism by which miotics lower intraocular pressure is not exactly known; however, contraction of the ciliary muscle apparently opens the intertrabecular spaces and facilitates aqueous humor outflow. There is also a decrease in the rate of inflow of aqueous humor. In angle-closure glaucoma, constriction of the pupil apparently pulls the iris away from the trabeculum, thereby relieving blockage of the trabecular meshwork.</p>