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Viscoelastic shear properties of the fresh porcine lens
  1. Ronald A Schachar1,
  2. Roger W Chan2,
  3. Min Fu3
  1. 1Department of Physics, University of Arlington, Arlington, Texas, USA
  2. 2Otolaryngology and Biomedical Engineering Departments, University of Texas Southwestern Medical Center, Dallas, Texas, USA
  3. 3Otolaryngology Department, UT Southwestern Medical Center, Dallas, Texas, USA
  1. Correspondence to: R A Schachar PO Box 601149, Dallas, TX 75229, USA; ron{at}2ras.com

Abstract

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, η′ = 0.16±0.1 Pa•sec, the damping ratio ζ = 4.06±1.25, and the phase shift, δ =  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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Footnotes

  • Competing interest: RAS has a financial interest in the surgical reversal of presbyopia

  • Published Online First 11 October 2006

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