What is the mechanism of hyperosmotic diuretic agents for glaucoma management?

• A. Dehydrates vitreous to reduce IOP rapidly in 10-15 minutes for 12-24 hours
• B. Increase outflow
• C. Decrease production
• D. Dilate pupil

Answer: (A)

Hyperosmotic diuretics lower intraocular pressure by creating an osmotic gradient that pulls water out of the eye's tissues into the bloodstream, leading to vitreous dehydration and a rapid drop in ocular volume. By reducing the vitreous volume, the pressure inside the eye falls quickly, which is why these agents are used in acute settings to normalize IOP before further management. They work quickly—often within minutes to an hour—and the effect lasts for several hours. They do not primarily increase aqueous outflow, nor do they decrease aqueous production, and they do not affect pupil size, which is why the mechanism is best described as vitreous dehydration via osmotic action.