Modifications in corneal biomechanics and intraocular pressure after deep sclerectomy

Purpose To compare preoperative and postoperative measurements of corneal biomechanical properties and intraocular pressure (IOP) using Goldmann applanation tonometry (GAT) and the ocular response analyzer (ORA, Reichert Inc, Depew, NY) in eyes undergoing deep sclerectomy with implant (DSCI). Methods Ninety eyes of 90 glaucomatous patients undergoing deep sclerectomy with SNOPER® implant and and 30 eyes of 30 normal subjects were included were included. Goldmann applanation IOP, central corneal thickness (CCT), and ORA measurements [corneal compensated IOP (IOPcc), Goldmann-correlated IOP (IOPg), corneal resistance factor (CRF), and corneal hysteresis (CH)] were taken the day before deep sclerectomy with collagen implant and on days 1, 8, and 30 and three months after surgery. Results Preoperative CH and CRF values of the glaucomatous patients were statistically significantly lower than the values in normal subjects. Corneal hysteresis values increased significantly on day 1 after DSCI, and then showed a statistically significant decrease up to day 30. GAT IOP and all the other ORA parameters changed significantly on day 1 after DSCI, but there was no time effect variation up to 3 months. Only CH showed variations up to 3 months after surgery. Conclusions CH statistically increased between preoperative and postoperative day 1 DSCI. On days 8 and 30, the change in CH values was statistically significant.