Which of the following is a direct parasympathomimetic used in glaucoma management?

• A. Atropine
• B. Dorzolamide 2%
• C. Pilocarpine 2%
• D. Timolol

Answer: (C)

Direct parasympathomimetics activate muscarinic receptors in the eye to cause the ciliary muscle to contract and the pupil to constrict. This action opens the angle and boosts outflow through the trabecular meshwork, which lowers intraocular pressure a key goal in glaucoma management. Pilocarpine is a direct-acting muscarinic agonist, so it fits this mechanism and has long been used to enhance drainage in glaucoma.

Atropine works in the opposite way—it blocks muscarinic receptors, causing dilation and cycloplegia, which does not help lower eye pressure. Dorzolamide is a carbonic anhydrase inhibitor; it reduces aqueous humor production rather than stimulating outflow. Timolol, a beta-blocker, also reduces production of aqueous humor but is not a cholinergic agent.