Which indirect acting cholinergic agonist is used in the preventive management of glaucoma?

• A. Physostigmine
• B. Demecarium
• C. Neostigmine
• D. Pyridostigmine

Answer: (B)

Indirect acting cholinergic agonists inhibit acetylcholinesterase, increasing acetylcholine at muscarinic receptors in the eye. This causes contraction of the ciliary muscle and sphincter pupillae, leading to increased aqueous humor outflow through the trabecular meshwork and a drop in intraocular pressure. For preventive glaucoma management, a long-acting agent is preferred to maintain ongoing outflow with less frequent dosing. Demecarium bromide is a long-acting acetylcholinesterase inhibitor used topically in the eye for this purpose, providing sustained cholinergic effect to help prevent progression. The other agents are either shorter-acting or used for different indications (systemic myasthenia gravis therapies or acute/non-prophylactic ocular use), making them less suitable for long-term preventive management of glaucoma.