SCIENTIFIC REPORT

Viscoelastic shear properties of the fresh porcine lens

Ronald A Schachar¹, Roger W Chan² and Min Fu³

¹ Department of Physics, University of Arlington, Arlington, Texas, USA
² Otolaryngology and Biomedical Engineering Departments, University of Texas Southwestern Medical Center, Dallas, Texas, USA
³ Otolaryngology Department, UT Southwestern Medical Center, Dallas, Texas, USA

Correspondence to:
Correspondence to:
R A Schachar
PO Box 601149, Dallas, TX 75229, USA; ron{at}2ras.com

Aim: To determine the viscoelastic properties of the porcine lens

Methods: Linear viscoelastic shear properties of the stroma of four porcine lenses were measured within 5 hours post-mortem, using sinusoidal oscillatory shear deformation. The elastic shear modulus, viscous shear modulus, dynamic viscosity, damping ratio, and phase shift of the lenses were quantified by a controlled-strain, linear simple-shear rheometer at frequencies of 10–50 Hz.

Results: The mean viscoelastic properties and their standard deviations across the frequencies examined were: the elastic shear modulus, G' = 6.2±4.0 Pa, the viscous shear modulus, G'' = 19.2±2.5 Pa, the dynamic viscosity, ' = 0.16±0.1 Pa•sec, the damping ratio = 4.06±1.25, and the phase shift, = 76°± 5.6°.

Conclusions: The measured viscoelastic shear properties of the porcine lens reflect a low dynamic viscosity with a high damping ratio. The porcine lens is viscoelastic and is more viscous than elastic. The magnitude of the complex shear modulus of the porcine lens, |G*|, is similar to the shear modulus of the young human lens. Understanding these viscoelastic properties of the natural lens may provide guidance in developing a lens substitute capable of accommodation in the post cataract patient.

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• Schachar, R. A, Pierscionek, B. K, Abolmaali, A., Le, T. (2007). The relationship between accommodative amplitude and the ratio of central lens thickness to its equatorial diameter in vertebrate eyes. Br. J. Ophthalmol. 91: 812-817 [Abstract] [Full Text]