PURPOSE: To detect the early effects of pars plana vitrectomy (PPV) combined with intravitreal gas tamponade on corneal biomechanics and compare these effects of sulfur hexafluoride (SF6) and perfluropropane (C3F8). METHODS: 19 eyes underwent PPV with C3F8, 14 eyes underwent PPV with SF6 tamponade and 16 eyes underwent PPV without tamponade. Corneal biomechanical parameters were measured preoperatively and at the first postoperative week by an ocular response analyzer. RESULTS: There were no significant differences of corneal hysteresis (CH), corneal resistance factor (CRF), corneal compensated intraocular pressure (IOPcc) and Goldmann-correlated intraocular pressure (IOPg) between the groups preoperatively. The mean CRF, IOPcc and IOPg significantly increased at the first postoperative week in the C3F8 group. In the SF6 group, CRF increased significantly but the increases in IOPcc and IOPg were not significant. In the PPV group, the increases in CRF, IOPcc and IOPg were not significant. The mean CH decreased in the C3F8, SF6 and PPV groups postoperatively but these results were not significant. No statistically significant differences were found between the changes of preoperative and postoperative CH, CRF and IOPg between the groups, but the increase in IOPcc was statistically significantly higher in the C3F8 group than the others. CONCLUSION: SF6 and C3F8 gas tamponade may affect corneal biomechanical parameters at the early postoperative period which should be related with surgery, gas tamponade or intraocular pressure changes.
PURPOSE: To detect the early effects of pars plana vitrectomy (PPV) combined with intravitreal gas tamponade on corneal biomechanics and compare these effects of sulfur hexafluoride (SF6) and perfluropropane (C3F8). METHODS: 19 eyes underwent PPV with C3F8, 14 eyes underwent PPV with SF6 tamponade and 16 eyes underwent PPV without tamponade. Corneal biomechanical parameters were measured preoperatively and at the first postoperative week by an ocular response analyzer. RESULTS: There were no significant differences of corneal hysteresis (CH), corneal resistance factor (CRF), corneal compensated intraocular pressure (IOPcc) and Goldmann-correlated intraocular pressure (IOPg) between the groups preoperatively. The mean CRF, IOPcc and IOPg significantly increased at the first postoperative week in the C3F8 group. In the SF6 group, CRF increased significantly but the increases in IOPcc and IOPg were not significant. In the PPV group, the increases in CRF, IOPcc and IOPg were not significant. The mean CH decreased in the C3F8, SF6 and PPV groups postoperatively but these results were not significant. No statistically significant differences were found between the changes of preoperative and postoperative CH, CRF and IOPg between the groups, but the increase in IOPcc was statistically significantly higher in the C3F8 group than the others. CONCLUSION:SF6 and C3F8 gas tamponade may affect corneal biomechanical parameters at the early postoperative period which should be related with surgery, gas tamponade or intraocular pressure changes.