[Comparison of intraocular pressure reduction in eyes with different intraocular tamponades after pars plana vitrectomy by 20% mannitol].

To investigate the efficacy of 20% mannitol in reducing intraocular pressure (IOP) in eyes with different intraocular tamponades after pars plana vitrectomy (PPV). Retrospective case-control study. Sixty-eight patients were administered with 20% mannitol and IOP was noted at regular intervals after simple PPV with ocular hypertension, including 24 males (26 eyes) and 44 females (46 eyes), aged (45.6±19.3) years. These cases were divided into three groups according to different tamponades: silicon-oil tamponade, 23 eyes; gas tamponade, 30 eyes; balanced salt solution (BSS), 19 eyes. The data were analyzed using the test, variance and test. There was a significant decrease in IOP in all patients after using 20% mannitol. The IOP in the group of silicon-oil decreased from (33.25±2.56) mmHg (1 mmHg=0.133 kPa) to (23.21±1.85) mmHg, with a maximum decrease of 30.10%; the reduction in the group of C(3)F(8) was from (33.25±2.84) mmHg to (12.15±1.12) mmHg, with a maximum decrease of 33.44%. The IOP of the two groups dropped to a minimum both at 75 minutes. In the group of BSS, the IOP decreased from (32.95±2.33) mmHg to (17.50±1.35) mmHg, and the maximum extent of the decrease was 45.82% at 45 minutes. The difference in the IOP among the three groups at 20 min, 30 min, 45 min and 60 min was statistically significant (34.02, 112.68, 122.07, 34.83, all 0.00). There were significant differences between the BSS group and the silicone-oil group (6.44, 13.04, 15.00, 17.11, all 0.00), and between the BSS group and the C(3)F(8) group (7.68, 12.56, 12.93, 13.61, all 0.00). In eyes with different intraocular tamponades, 20% mannitol was useful for short-term IOP reduction after vitrectomy, especially in those with BSS within one hour. But after 75 minutes, there was no statistically significant difference between groups. .