Snapshot A 56-year-old man presents to the emergency department with severe eye pain, headache, blurry vision, and seeing halos around lights. His symptoms occured after he was in the movie theatre. Medical history is noncontributory. On physical examination, there is reduced visual acuity and a mid-dilated right pupil that is cloudy and poorly responsive to light. Intraocular pressure is 62 mmHg (normal is 8-20 mmHg.) The on call ophthalmologist is emergently consulted and in the meantime the patient is given timolol, apraclonidine, and pilocarpine drops that are administered one minute apart. (Angle-closure glaucoma) Introduction Glaucoma is an optic neuropathy leading to optic nerve head atrophy and is typically associated with an elevated intraocular pressure The goal of treatment is to decrease intraocular pressure recall that aqueous humor production begins in the nonpigmented epithelium of the ciliary body α-agonists, β-blockers, and carbonic anhydrase inhibitors can act here the aqueous humor then flows from the posterior chamber → anterior chamber → trabecular meshwork → canal of Schlemm the uveoscleral outflow can be influenced by prostaglandin analogs the trabecular outflow can be influenced by cholinomimetics Glaucoma Drugs Medication Mechanism of Action Side Effects α2-agonists Brimonidine ↓ aqueous humor production Allergic and follicular conjunctivitis Contact dermatitis Blurry vision β-blockers Timolol, betaxolol, and carteolol ↓ aqueous humor production No changes in pupil size or vision Carbonic anhydrase inhibitor Acetazolamide ↓ aqueous humor production via inhibition of carbonic anhydrase No changes in pupil size or vision Cholinomimetics Pilocarpine and carbachol ↑ aqueous humor outflow via ciliary muscle contraction by directly stimulating cholinergic receptors Physostigmine and echothiopate ↑ aqueous humor outflow via ciliary muscle contraction by indirectly stimulating cholinergic receptors Miosis Cyclospasm Prostaglandins Bimatoprost and latanoprost are PGF2α analogs that ↑ aqueous humor outflow Periocular hyperpigmentation Increased and/or misdirected eyelash growth