Significance of corneal biomechanical properties in patients with progressive normal-tension glaucoma

Aim To investigate the clinical significance of corneal biomechanical properties assessed using an ocular response analyser in patients with progressing normal-tension glaucoma (NTG). Methods In this retrospective study, we included 82 eyes of 82 NTG patients who had been receiving topical anti-glaucoma medications. Patients were allocated to two groups based on the mean value of corneal hysteresis (CH) and the status of progression. The assessment of progression was based on the trend analysis using mean deviation slope. Uni-and multivariable logistic analyses were constructed to identify factors associated with increased odds of progression, including CH, central corneal thickness (CCT), and retinal nerve fibre layer (RNFL) thickness. Results Forty-six eyes (56.1%) reached the progression criteria. Eyes with progression had lower CCT (530.2 +/- 38.6 vs 549.4 +/- 38.3 mu m, p= 0.03), thinner average RNFL thickness (70.6 +/- 16.1 vs 82.8 +/- 17.4 mu m, p< 0.01), lower CH (9.4 +/- 1.3 vs 10.8 +/- 1.4 mm Hg, p< 0.01), and lower corneal resistance factor (9.3 +/- 1.3 vs 10.4 +/- 1.8 mm Hg, p< 0.01) than eyes without progression. CH and CCT were significantly correlated (r= 0.44, p< 0.01). Upon multivariable analysis, CH (beta (B)= 0.32 per mm Hg lower, p< 0.01) and average RNFL thickness (beta= 0.96 per mu m lower, p= 0.04) remained statistically significant. Conclusions Corneal biomechanical properties are correlated and associated with the progression of visual field damage in NTG patients. These findings suggest that CH can be used as one of the prognostic factors for progression, independent of corneal thickness or intraocular pressure.