Effect of Intravenous Mannitol on Intraocular Pressure in Vitrectomized Silicone-Oil-Filled Eyes

Purpose: To evaluate the effect of intravenous mannitol (IVM) on intraocular pressure (IOP) in vitrectomized eyes. Methods: Thirty-one patients with raised IOP after retinal surgery with silicone oil injection were included. Patients were administered IVM (20% solution, 1g/Kg, over 30 minutes) and IOP was noted at regular intervals. IOP reduction in vitrectomized eyes (Group 1) was compared with the normal eyes (Group 2). Result: Percentage IOP reduction was higher in Group 1 than in Group 2 at all time intervals, 24.5% vs. 19.2% at 15 minutes (p=0.34), 22.6% vs. 9.8% at 45 minutes (p=0.003), 19.1% vs. 9.9% at two hours (p=0.023), and 16.1% vs. 7.8% at four hours (p=0.04), respectively. In Group 1, 40% eyes had an IOP reduction of 2-6 mmHg while 30% eyes had IOP reduction >6 mmHg at four hours post-IVM. Conclusion: IVM is useful for short-term IOP reduction in vitrectomized eyes. IOP reduction is independent of baseline IOP, and sustained and higher as compared to normal eyes.