Corneal and optic nerve head biomechanical changes after deep sclerectomy

Abstract

PurposeTo evaluate corneal and optic nerve head (ONH) biomechanical changes following nonpenetrating deep sclerectomy (DS).MethodsForty‐nine eyes undergoing DS were prospectively studied. Changes in corneal hysteresis (CH) and corneal resistance factor (CRF) using the Ocular Response Analyzer, as well as changes in prelaminar thickness, cupping and lamina cribrosa (LC) position using EDI technology before surgery and 3 months postoperatively were obtained. Simple and multiple linear regression models were used to determine predictors of ONH changes including age, corneal central thickness (CCT) and axial length (AL).ResultsMean corneal compensated IOP significantly decreased by 27.9% (P < 0.001). Mean CH increased and CRF decreased by 18.4% and 10.1% respectively (P < 0.001) and both were significantly correlated with IOP reduction (P < 0.001). There was a significant reversal of ONH cupping mainly due to a prelaminar tissue thickening (P < 0.001). Mean preoperative AL correlated with the preoperative LC thickness (−0.459, P = 0.012) and a further anterior displacement of LC postoperatively (0.377, P = 0.044). A significant association was found between ONH cupping reversal and both preoperative IOP (P = 0.046) and preoperative CRF (P = 0.002).ConclusionsCH increased and CRF decreased significantly 3 months after NPDS and these changes correlated with IOP reduction. A significant cupping reversal mainly due to changes in prelaminar tissue thickness was observed. The magnitude of IOP reduction was the most significant factor in both corneal and ONH biomechanical changes.