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In Vivo Biomechanical Changes Associated With Keratoconus Progression
Prema Padmanabhan1, Bernardo T Lopes2,3, Ashkan Eliasy2
1Department of Cornea and Refractive Surgery, Sankara Nethralaya, Chennai, India.
Current Eye Research
|April 6, 2022
Summary
Keratoconus progression causes significant corneal biomechanical deterioration, evidenced by reduced corneal stiffness. The stress-strain index (SSI) and integrated inverse radius (IIR) effectively track these changes in vivo.
Area of Science:
- Ophthalmology
- Biomechanical Engineering
- Corneal Science
Background:
- Keratoconus (KC) is a progressive thinning disorder of the cornea.
- Assessing biomechanical deterioration is crucial for understanding KC progression and treatment efficacy.
- In vivo assessment of corneal biomechanics provides valuable insights into disease progression.
Purpose of the Study:
- To evaluate the in vivo biomechanical changes associated with keratoconus progression.
- To identify key biomechanical parameters that reflect disease advancement.
Main Methods:
- Preoperative examinations of 32 progressive KC patients undergoing corneal cross-linking (CXL).
- Corneal tomography (Pentacam HR) and biomechanical analysis (Corvis ST) were performed.
- Biomechanical parameters were assessed at two time points, prior to CXL.
Main Results:
- Significant deterioration in ABCD grading system parameters was observed with KC progression.
- Corneal stiffness significantly decreased, indicated by reduced stress-strain index (SSI) and Stiffness Parameter A1 (SP-A1).
- Integrated Inverse Radius (IIR) and deflection amplitude (DA) ratio increased significantly, also reflecting reduced corneal stiffness. SSI and IIR showed minimal overlap, indicating sensitivity to changes.
Conclusions:
- In vivo evidence confirms biomechanical deterioration accompanies keratoconus progression.
- SSI and IIR are sensitive indicators of corneal stiffness reduction in progressive keratoconus.
- These parameters show potential for monitoring keratoconus progression and treatment response.
