Thermal and biomechanical parameters of porcine cornea.

摘要: Purpose New methods in refractive surgery require a considerable understanding of the material "cornea" and are often studied by theoretical modeling order to gain insight into procedure an optimized approach technique. The quality these models is highly dependent on preciseness its input parameters. Porcine cornea used as model preclinical studies because similarity man availability. Methods important physical parameters for biomechanical deformation, heat conduction, collagen denaturation kinetics have been determined porcine cornea. Experimental include densitometry, calorimetry, turbidimetry, tensile tests, stress relaxation, hydrothermal isometric tension measurements. Results density was measured p = 1062+/-5 kg/m3, capacity gave c 3.74+/-0.05 J/gK. stress-strain relation corneal strips represented third approximation where secant modulus yields about Esec approximately equal 0.4 MPa small strains less than 2%. normalized relaxation described exponential fit over time. process characterized specific temperatures which can be related change mechanical properties. Denaturation according Arrhenius yielding activation energy deltaEa 106 kJ/mol phase transition entropy deltaS 39 J/(mol x K). Conclusions established set characterizes reliable way that creates basis models. It furthermore gives direct hints how treat certain techniques.