Abstract
Purpose: :
To use osmotic swelling as a driving force to measure the elasticity of the porcine lens capsule.
Methods: :
We developed a simple model to simulate the swelling lens as a lumped system, accounting for the permeability of the membrane to the solvent, the osmotic pressure inside the lens, and the elasticity of the capsule. Porcine lenses were submerged in pure H2O, 0.2% and 0.5% saline solutions. Sequential images taken during osmotic swelling were captured and analyzed in MATLAB. Fitting the experimental data to the model provided an estimate of the elasticity of the lens capsule.
Results: :
The calculated modulus was 0.21 ± 0.08 MPa for pure H2O (n = 7), 0.24± 0.06 MPa for 0.2% saline solution (n = 7), and 0.15± 0.04 MPa for 0.5% saline (n = 7) solution. The difference in these values were not statistically significant when pure H2O was compared with 0.2% saline solution (p = 0.37) and 0.5% saline solution (p = 0.10).
Conclusions: :
Our experimental model provides an estimation of the modulus of elasticity of the porcine lens capsule without requiring dissection of the lens. Estimated values of the modulus are within the range of those obtained by other methods (Krag and Andreassen, Exp Eye Res 62:253-60, 1996; Heistand et al., Biomech Model Mechanobiol., 4(2-3):168-77, 2005).The new method could be employed in smaller animals, such as mice, for which conventional mechanical stretching methods are not practical.
Keywords: accomodation • cataract