Vision and Ophthalmology Pharmacology and Medications 1 — Questions and Answers
Question 1: Timolol, a beta-blocker used to treat glaucoma, lowers IOP by:
- Increasing trabecular outflow
- Decreasing aqueous humor production by the ciliary body (Correct answer)
- Increasing uveoscleral outflow
- Constricting the pupil
Correct answer: Decreasing aqueous humor production by the ciliary body
Timolol is a non-selective beta-adrenergic blocker that reduces IOP by decreasing aqueous humor production from the ciliary body epithelium.
Question 2: Prostaglandin analogs (e.g., latanoprost) lower IOP primarily by:
- Reducing aqueous production
- Increasing uveoscleral and trabecular outflow (Correct answer)
- Constricting the pupil (miosis)
- Blocking carbonic anhydrase
Correct answer: Increasing uveoscleral and trabecular outflow
Prostaglandin analogs are the most potent topical IOP-lowering agents, working primarily by enhancing uveoscleral outflow through the ciliary muscle.
Question 3: Which class of glaucoma medication is contraindicated in patients with sulfonamide allergy?
- Beta-blockers
- Prostaglandin analogs
- Carbonic anhydrase inhibitors (Correct answer)
- Alpha-2 agonists
Correct answer: Carbonic anhydrase inhibitors
Carbonic anhydrase inhibitors (dorzolamide, brinzolamide topically; acetazolamide orally) are sulfonamide derivatives and may cause cross-reactivity in sulfonamide-allergic patients.
Question 4: Tropicamide eye drops are used to dilate the pupil for fundus examination. What is their mechanism?
- Alpha-1 adrenergic agonist
- Anticholinergic (muscarinic antagonist) (Correct answer)
- Beta-2 adrenergic agonist
- Dopamine agonist
Correct answer: Anticholinergic (muscarinic antagonist)
Tropicamide blocks muscarinic acetylcholine receptors in the iris sphincter and ciliary muscle, causing mydriasis and cycloplegia.
Question 5: Pilocarpine eye drops are used in acute angle-closure glaucoma. What is their mechanism of action?
- Block beta receptors to reduce aqueous production
- Stimulate muscarinic receptors to cause miosis and open the drainage angle (Correct answer)
- Inhibit carbonic anhydrase
- Stimulate alpha-2 receptors
Correct answer: Stimulate muscarinic receptors to cause miosis and open the drainage angle
Pilocarpine is a muscarinic agonist that constricts the pupil (miosis) and contracts the ciliary muscle, pulling the peripheral iris away from the trabecular meshwork to open the angle.
Question 6: Fluoroquinolone antibiotic eye drops (e.g., moxifloxacin) are commonly used to treat which ophthalmic condition?
- Viral conjunctivitis
- Bacterial keratitis and conjunctivitis (Correct answer)
- Allergic conjunctivitis
- Fungal keratitis
Correct answer: Bacterial keratitis and conjunctivitis
Topical fluoroquinolones provide broad-spectrum bactericidal coverage and are first-line treatment for bacterial keratitis and severe bacterial conjunctivitis.
Vision and Ophthalmology Pharmacology and Medications 1
Timolol, a beta-blocker used to treat glaucoma, lowers IOP by: