Intravitreal silicone oil induced changes in corneal biomechanics

Our aim was to detect the early effects of pars plana vitrectomy (PPV) combined with intravitreal silicone oil (SO) on corneal biomechanics. 19 eyes underwent PPV with SO tamponade (group 1) and 16 eyes underwent. PPV without tamponade (group 2). Corneal biomechanical parameters were measured preoperatively and at the first postoperative month by ocular response analyzer. The mean preoperative intraocular pressure (IOP) by Goldmann applanation tonometry (GAT) and the mean corneal-compensated intraocular pressure (IOPcc) were significantly lower in group 1 than group 2 (p = 0.005, p = 0.002, respectively). The mean preoperative corneal hysteresis (CH) and corneal resistance factor (CRF) were significantly higher in group 1 than group 2 (p = 0.017, p = 0.002, respectively). However, the difference in Goldmann-correlated intraocular pressure (IOPg) between the groups was not significant (p = 0.360). In group 1, IOPcc, IOPg and IOP-GAT significantly increased postoperatively (p = 0.002, p = 0.004, p = 0.002, respectively) but CH and CRF decreased (p = 0.007, p = 0.153, respectively). In group 2, IOPcc, IOPg and IOP (GAT) increased postoperatively but the differences were not significant (p = 0.851, p = 0.693, p = 0.336, respectively). The mean CRF increased significantly (p = 0.026) postoperatively but the decrease in CH was not significant (p = 0.196). Statistically significant differences were found in the changes of preoperative and postoperative means of IOPcc, IOPg, IOP-GAT and CRF between the groups (p = 0.024, p = 0.037, p = 0.014, p = 0.006, respectively). However, the difference in the decreases in CH between the two groups was not statistically significant (p = 0.206). SO tamponade may affect corneal biomechanical parameters in the early postoperative period, which may be related to the surgery itself, SO tamponade or IOP changes.