Which diuretic class can cause acute transient myopia and acute angle-closure glaucoma?

• A. Loop diuretics
• B. Thiazides
• C. Potassium-sparing diuretics
• D. Carbonic anhydrase inhibitors

Answer: (B)

Carbonic anhydrase inhibitors can cause acute transient myopia with a risk of acute angle-closure glaucoma. These drugs block carbonic anhydrase in the ciliary processes, which not only lowers aqueous humor production but can trigger ciliochoroidal effusion. This effusion pushes the iris-lens diaphragm forward, shallowing the anterior chamber and narrowing or closing the angle. The result is a sudden rise in intraocular pressure and a reversible myopic shift, often presenting within hours to days of starting the medication. This ocular adverse effect is classically linked to acetazolamide (and other sulfonamide carbonic anhydrase inhibitors, including topiramate), rather than to the loop or thiazide diuretics, which do not typically cause this presentation.