Effect of Mannitol on Intraocular Pressure in Vitrectomized and Nonvitrectomized Eyes: A Prospective Comparative Study

Purpose: To compare the effect of mannitol in reducing intraocular pressure (IOP) in vitrectomized and nonvitrectomized eyes. Materials and Methods: Prospective comparative case study. Eyes with IOP≥40 mm Hg were included. Eyes which are vitrectomized and silicon oil filled were classified as group 1, and nonvitrectomized open-angle eyes were classified as group 2. Mannitol (20%, 1 g/kg) was administered intravenously over 30 minutes, and IOP was recorded at 30 minutes interval till 2 hours and at the third and fourth hour from the start of mannitol. Results: Thirty eyes (patients) were recruited in each group. Mean (SD) IOP reduced from 48.5±5.2 to 43.7±8 at 30 minutes, 40.7±8.4 at 60 minutes, 37.3±9.6 at 90 minutes, 35.6±10.4 at 2 hours, 34±10.7 at 3 hours, and 33±11.2 mm Hg at 4 hours in group 1, and from 48.9±6.5 to 43.2±8.6 at 30 minutes, 40.2±7.8 at 60 minutes, 36.7±7.3 at 90 minutes, 35.1±7.7 at 2 hours, 34.2±8.8 at 3 hours, and 35.7±9.4 mm Hg at 4 hours in group 2. There was a significant reduction in IOP at each time point compared with baseline in both the groups ( P <0.001). There was no significant difference in IOP between the 2 groups at each time point. Conclusion: Mannitol reduces IOP significantly in both vitrectomized and nonvitrectomized eyes.