Corneal Stiffness and Modulus of Normal-Tension Glaucoma in Chinese

center dot PURPOSE: To assess and compare the corneal biome-chanics of normal-tension glaucoma (NTG), high-tension glaucoma (HTG), and normal controls based on stiffness and modulus. The correlations among central corneal thickness (CCT), visual field, retinal nerve fiber layer (RNFL) thickness, and corneal biomechanics in glaucoma eyes were also evaluated. center dot DESIGN: A prospective, cross-sectional, comparative study. center dot METHODS: This study included 334 eyes of 108 NTG patients, 113 HTG patients, and 113 control subjects at Zhongshan Ophthalmic Center, Sun Yat-Sen Uni-versity. Corneal biomechanics were evaluated using a corneal indentation device (CID) and corneal visualiza-tion Scheimpflug technology (Corvis ST). Visual field and RNFL thickness were obtained using standard au-tomated perimetry and spectral-domain optical coherence tomography. One-way analyses of variance with Bonfer-roni post hoc tests and a multivariable linear regression analysis with adjustment were conducted. Correlations among corneal biomechanical parameters, CCT, visual field, and RNFL thickness were analyzed. center dot RESULTS: The corneal stiffness of the NTG patients (71.0 +/- 10.9 N/m) was significantly lower than that of the HTG patients (77.3 +/- 15.6 N/m; P = .001) and the CCT-and IOP-matched normal controls (75.6 +/- 11.0 N/m; P = .023). The patients in the NTG group had lower corneal stiffness than those in the control group ( 0 =-4.88, 95% CI-9.002,-0.758; P = .020) after adjusting for confounders. Stiffness was positively corre-lated with CCT in the NTG group ( P = .028) but not in the HTG group ( P = .509). There was no significant cor-relation ( P > .05) between corneal biomechanics, visual field, or RNFL thickness. center dot CONCLUSIONS: The corneas of NTG patients were softer than those of HTG patients and con-trols, as assessed by CID, which were associated with thinner CCT. These might suggest differ-ent ocular biomechanical properties in NTG and HTG. (Am J Ophthalmol 2022;242: 131-138. (c) 2022 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY-NC-ND license ( http://creativecommons.org/licenses/by-nc-nd/4.0/ ))

Automated summary

This study assessed and compared corneal biomechanics in normal-tension glaucoma (NTG), high-tension glaucoma (HTG), and normal controls. The results showed that the corneas of NTG patients were softer than those of HTG patients and controls, which was associated with thinner corneal thickness.