Comparative study of corneal strip extensometry and inflation tests

Area of Science:

• Ophthalmology
• Biomaterials Science
• Mechanical Engineering

Background:

• Strip extensometry is a simple method for corneal biomechanics but often considered less reliable than inflation tests.
• Previous studies favored inflation tests for determining corneal constitutive relationships, Young's modulus, and hysteresis behavior.

Purpose of the Study:

• To address the deficiencies of strip extensometry in corneal biomechanics.
• To present a mathematical procedure to improve the accuracy of strip extensometry for material property determination.
• To compare strip extensometry with a new analysis to trephinate inflation tests.

Main Methods:

• Discussed limitations of strip extensometry for corneal biomechanical analysis.
• Developed and applied a mathematical procedure to correct for strip test deficiencies.
• Conducted strip extensometry and trephinate inflation tests on 10 pairs of porcine corneas.
• Performed mathematical back analysis on test results to determine stress-strain behavior.

Main Results:

• The new mathematical analysis significantly improved the reliability of strip extensometry.
• Corneal material properties obtained via corrected strip extensometry closely matched those from inflation tests.
• The stress-strain behavior derived from the enhanced strip extensometry aligned well with inflation test data.

Conclusions:

• Strip extensometry, when combined with the presented mathematical procedure, offers a reliable method for studying corneal biomechanics.
• This approach enhances the accuracy of determining corneal material properties, including stress-strain behavior.
• The findings suggest a more accessible and accurate method for corneal biomechanical research.