Intravenous Mannitol, a parenteral obligatory osmotic diuretic, reduces Intraocular pressure(IOP) by increasing the Plasma osmolality and drawing water from the eye into the circulation. The dose, concentration and administration depends on severity of condition, fluid requirement and urinary output . For reduction of  IOP: In adults, a dose of 1 to 2 g/kg body weight as 15% – 25% solution and in pediatric patients, 1 to 2 g/kg body weight or 30 to 60 g/m² over 30 to 60 minutes. In debilitated patients, 500 mg/kg may be sufficient. Preoperatively, it should be given one to one and a half hours before surgery to achieve maximum IOP reduction. Onset of action in 15–30 minutes, reaches a maximum effect in 30–60 minutes with duration of action approximately 6 hours. It is administered with caution in patients with cardiac, renal, and hepatic disease. Headache, nausea, vomiting, and diuresis are common side effects.