Comparison of bilateral differential characteristics of corneal biomechanics between keratoconus and normal eyes

Abstract

Purpose: To compare bilateral differences in corneal biomechanics between keratoconus and normal eyes.Methods: In this case-control study, 346 eyes of 173 patients (aged 22.1 ± 6.1 years) with keratoconus (KC group) and 378 eyes of 189 patients (aged 26.7 ± 5.6 years) with ametropia (control group) were enrolled. Corneal tomography and biomechanical properties were examined using Pentacam HR and Corvis ST, respectively. The corneal biomechanical parameters were compared between eyes with forme fruste keratoconus (FFKC) and normal eyes. Bilateral differences in corneal biomechanical parameters were compared between the KC and control groups. Receiver operating characteristic (ROC) analysis was used to assess discriminative efficacies.Results: The areas under the ROC curves (AUROCs) of stiffness parameter at the first applanation (SP-A1) and Tomographic and Biomechanical Index (TBI) for identifying FFKC were 0.641 and 0.694, respectively. The bilateral differential values of major corneal biomechanical parameters were significantly increased in the KC group (all p < 0.05), except for the Corvis Biomechanical Index (CBI). The AUROCs of the bilateral differential values of the deformation amplitude ratio at 2 mm (ΔDAR2), Integrated Radius (ΔIR), SP-A1 (ΔSP-A1), and the maximum inverse concave radius (ΔMax ICR) for discriminating keratoconus were 0.889, 0.884, 0.826, and 0.805, respectively. The Logistic Regression Model-1 (comprising of ΔDAR2, ΔIR, and age) and the Logistic Regression Model-2 (comprising of ΔIR, ΔARTh, ΔBAD-D, and age) had AUROCs of 0.922 and 0.998, respectively, for discriminating keratoconus.Conclusion: The bilateral asymmetry of corneal biomechanics was significantly increased in keratoconus compared with normal eyes, which may be helpful for the early detection of keratoconus.

Squishy matters – Corneal mechanobiology in health and disease

“…Notwithstanding corneal thickness and curvature, the severity of biomechanical characteristics of keratoconic groups were stratified using stress-strain index measurements through correlations with age, biomechanically corrected intraocular pressure, and central corneal thickness ( Padmanabhan et al, 2022 ). These studies also reveal that an asymmetry exists in biomechanical properties determined clinically, using Pentacam HR and Corvis ST, when comparing the two eyes of keratoconic patients and this asymmetry has been posited to be an early predictor of disease progression ( Xian et al, 2023 ).…”

Keratoconus cone location influences ocular biomechanical parameters measured by the Ocular Response Analyzer

“…Given the known asymmetry in disease severity and in biomechanical parameters between the eyes in keratoconus [ 22 – 25 ], individual eyes of all participants were treated independently. If one eye had a central cone, and the fellow eye had a peripheral cone, then the two eyes were binned into separate cohorts.…”