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Corneal biomechanical characterization from in‐vitro eye inflation, optical coherence tomography and finite element modeling
Author(s) -
KLING S,
PEREZ P,
ORTIZ S,
MARCOS S
Publication year - 2011
Publication title -
acta ophthalmologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.534
H-Index - 87
eISSN - 1755-3768
pISSN - 1755-375X
DOI - 10.1111/j.1755-3768.2011.2373.x
Subject(s) - cornea , sclera , optical coherence tomography , materials science , finite element method , biomechanics , glaucoma , biomedical engineering , corneal topography , deformation (meteorology) , ophthalmology , anatomy , optics , medicine , physics , composite material , structural engineering , engineering
Purpose Absolute changes in corneal surface area, volume, apex displacement and limbus deformation during in‐vitro inflation were used to determine biomechanical properties of the corneal tissue Methods Whole‐globe and corneal button inflation experiments were performed on porcine eyes placed in a temperature and humidity controlled chamber. IOP was increased and decreased (15‐55‐15 mmHg) at 5mmHg steps, each time acquiring a 3‐D imaging with a customized spectral anterior segment OCT imaging system. Raw images were corrected from optical and fan distortion. Limbus and apex were detected and the corneal volume and surface area were calculated. The experimental data served as input to optimize a 2D‐axis‐symmetric, viscoelastic finite‐element‐model (with cornea‐limbus‐sclera geometry) written in ANSYS to retrieve elastic (Young’s modulus) and viscoelastic (Prony and retardation time constants) corneal biomechanical properties. Results The experimental corneal response upon inflation was well predicted by the FEM simulations. The central cornea deformed more (the apex raised by 60.8 μm at maximum IOP) than the limbal region (factor 3/4 in radial expansion). The limbus expansion caused a flattening of the angle between cornea and sclera. Mean corneal surface was 226 mm2 and changed less than 1% Poisson’s ratio was found to be 0.49 and Young’s modulus 1.24 MPa Conclusion Measuring and understanding corneal biomechanical parameters is important to predict the outcome of different surgical treatments and could be useful to early detection of several corneal pathologies. Quantitative high resolution OCT imaging in combination with FEM simulation allows to accurately determine meaningful mechanical parameters.