Which medication inhibits aqueous humor production as part of reducing intraocular pressure in acute angle-closure glaucoma?

• A. Acetazolamide
• B. Mannitol
• C. Timolol
• D. Pilocarpine

Answer: (C)

Timolol works by directly reducing the production of aqueous humor. It’s a topical beta-blocker that blocks beta receptors in the ciliary body, lowering cAMP and decreasing the secretion of aqueous humor. This rapid, local action helps lower intraocular pressure quickly in acute angle-closure glaucoma and is commonly used as part of initial therapy.

While acetazolamide also decreases aqueous humor formation by inhibiting carbonic anhydrase, it’s systemic and carries potential metabolic side effects, so in the acute setting a topical beta-blocker is often preferred for fast, targeted reduction. The other options act by different mechanisms: mannitol lowers IOP through osmotic effects, and pilocarpine increases outflow rather than production.