CPOA Ocular Pharmacology 2 — Questions and Answers
Question 1: Which class of medication is commonly used as a cycloplegic agent to paralyze the ciliary muscle during refraction?
- Antihistamines
- Anticholinergics (Correct answer)
- Beta-blockers
- Prostaglandin analogs
Correct answer: Anticholinergics
Anticholinergic agents such as cyclopentolate and atropine block muscarinic receptors, paralyzing the ciliary muscle to prevent accommodation.
Question 2: Timolol maleate is classified as which type of glaucoma medication?
- Alpha-2 agonist
- Carbonic anhydrase inhibitor
- Prostaglandin analog
- Non-selective beta-blocker (Correct answer)
Correct answer: Non-selective beta-blocker
Timolol is a non-selective beta-adrenergic blocker that reduces aqueous humor production by the ciliary body.
Question 3: A patient is prescribed latanoprost eye drops. Which side effect should you warn them about?
- Increased heart rate
- Iris color change (Correct answer)
- Pupil dilation
- Dry mouth
Correct answer: Iris color change
Prostaglandin analogs like latanoprost can cause increased iris pigmentation (heterochromia) with long-term use.
Question 4: What is the mechanism by which pilocarpine lowers intraocular pressure?
- Decreases aqueous production
- Increases uveoscleral outflow
- Opens trabecular meshwork by contracting ciliary muscle (Correct answer)
- Blocks prostaglandin synthesis
Correct answer: Opens trabecular meshwork by contracting ciliary muscle
Pilocarpine is a cholinergic agent that contracts the ciliary muscle, pulling the scleral spur and widening the trabecular meshwork to increase aqueous outflow.
Question 5: Which topical anesthetic has the FASTEST onset of action?
- Tetracaine
- Proparacaine (Correct answer)
- Benoxinate
- Cocaine
Correct answer: Proparacaine
Proparacaine (proxymetacaine) has the fastest onset of action at approximately 20 seconds and is less irritating than tetracaine.
Question 6: Acetazolamide, an oral carbonic anhydrase inhibitor, lowers IOP by which mechanism?
- Increasing uveoscleral outflow
- Decreasing aqueous humor production (Correct answer)
- Miosis-induced trabecular outflow
- Reducing episcleral venous pressure
Correct answer: Decreasing aqueous humor production
Acetazolamide inhibits carbonic anhydrase in the ciliary body epithelium, reducing bicarbonate and aqueous humor secretion.
Question 7: Which preservative found in many ophthalmic solutions is associated with corneal epithelial toxicity with long-term use?
- Sodium chloride
- Benzalkonium chloride (Correct answer)
- Boric acid
- Polyethylene glycol
Correct answer: Benzalkonium chloride
Benzalkonium chloride (BAK), a quaternary ammonium compound, can disrupt the corneal epithelial cell membrane with chronic exposure.
CPOA Ocular Pharmacology 2
Which class of medication is commonly used as a cycloplegic agent to paralyze the ciliary muscle during refraction?