A patient with narrow-angle glaucoma is mistakenly prescribed pilocarpine. Which of the following best describes the expected effect on the pupil and intraocular pressure?
- A Mydriasis leading to further angle closure and raised IOP
- B Cycloplegia preventing accommodation and worsening angle closure
- C Miosis that opens the iridocorneal angle and reduces IOP ✓
- D No pupillary change because pilocarpine only acts on ciliary muscle
Correct answer: C. Miosis that opens the iridocorneal angle and reduces IOP
Explanation
Pilocarpine is a direct-acting muscarinic agonist that contracts the iris sphincter (M3), producing miosis. In narrow-angle glaucoma, this pulls the peripheral iris away from the trabecular meshwork, deepening the anterior chamber angle and facilitating aqueous outflow. It also contracts the ciliary muscle, which pulls the scleral spur and opens the trabecular meshwork further. Pilocarpine is actually used as a miotic in angle-closure glaucoma attacks.
Reference: KD Tripathi, Essentials of Medical Pharmacology, 8th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.