Which statement about oral carbonic anhydrase inhibitors is true?

• A. They improve tear production
• B. They have no systemic effects
• C. They can cause metallic taste
• D. They only treat conjunctivitis

Answer: (C)

Oral carbonic anhydrase inhibitors work systemically to lower intraocular pressure by reducing bicarbonate formation in the ciliary body, which decreases aqueous humor production. Because they act in the whole body, they produce systemic side effects, including dysgeusia—a metallic taste. This makes the statement about a metallic taste true. They do have systemic effects, so claiming no systemic effects is incorrect, and they don’t improve tear production or treat conjunctivitis.