<prompt> Hyperosmolar agents in glaucoma acts by ?Increasing aqueous outflowDecreasing vitreous volumeDecrease aqueous productionFacilitate uveoscleral outflow  <response>: To decrease vitreous volume: Preoperative use of hyperosmotic agents like 20 percent mannitol or oral glycerol is suggested. Mechanism of action:Hyperosmotic agents increasethe plasma tonicity. Thus, the osmotic pressuregradient created between the blood and vitreousdraws sufficient water out of the eyeball, therebysignificantly lowering the IOP. Ref.AK Khurana 4th edition page no 426 