Quantification of corneal biomechanical properties by optical coherence elastography and a Lamb wave model

Abstract

 

Purpose

 

To quantitatively assesse the corneal viscoelasticity by using optical coherence elastography (OCE) and a Lamb wave model.

 

Methods

 

Air-pulse OCE experiments were conducted on porcine corneas to obtain the elastic displacement distributions which behaved as an elastic wave. Phase velocities of the air-pulse induced elastic waves were extracted by spectral analysis and used for calculating the Young’s moduli of the samples using the Rayleigh-Lamb frequency equation (RLFE). For cornea, the RLFE was modified to consider the effect of the aqueous humor. Experiments were performed on 2% agar phantoms (n=3) and then applied to porcine corneas (n=3) in situ.

 

Results

 

Validation experiments were performed on 2% agar phantoms (Figure a) and compared with uniaxial compressional tests (Figure b), which demonstrated the accuracy and feasibility of the RLFE method to reconstruct sample’s mechanical properties. Figure c demonstrates results from RLFE application to process OCE data from porcine corneas: the Young’s moduli were estimated to be ~60 kPa with a shear viscosity ~0.33 Pa∙s.

 

Conclusions

 

OCE combining RLFE is a promising method for noninvasive quantification of the corneal biomechanical properties and may potentially be useful for clinical ophthalmological applications.  

 

Validation experiments were performed on 2% agar phantoms (Figure a) and compared with uniaxial compressional tests (Figure b). Figure c demonstrates results for porcine corneas: the Young’s moduli were estimated to be ~60 kPa with a shear viscosity ~0.33 Pa∙s.