Which statement about first-line glaucoma medications is correct?

• A. They are prostaglandin analogs
• B. They are beta blockers
• C. They are cholinergic agents
• D. They are alpha agonists

Answer: (C)

Prostaglandin analogs are the preferred first-line therapy for primary open-angle glaucoma because they lower intraocular pressure effectively by increasing uveoscleral outflow, providing large and consistent reductions with a convenient once-daily dosing regimen and minimal systemic side effects. Their overall tolerability and ease of use tend to lead to better adherence, which is crucial for long-term control of glaucoma.

Cholinergic agents, while they can reduce IOP by enhancing outflow through the trabecular meshwork, are not first-line due to practical drawbacks: they require more frequent dosing, cause pupil constriction (miosis) and accommodation changes that can blur vision and are uncomfortable for nighttime use, and they have less predictable long-term efficacy and tolerability.

Beta blockers, though historically common, decrease aqueous production but carry systemic risks such as bradycardia, hypotension, and, in susceptible patients, bronchospasm, which limits their desirability as first-line options when prostaglandin analogs are available.

Alpha agonists can lower IOP but often cause allergic conjunctivitis and dry mouth or fatigue, and they generally don’t match prostaglandins in efficacy or tolerability for first-line use.