Abstract
The ocular lens stiffens dramatically with age, resulting in a loss of function. However, the mechanism of stiffening remains unknown, at least in part due to difficulties in making reliable measurements of the intrinsic mechanical properties of the lens. Recent experiments have employed manual compression testing to evaluate the stiffness of murine lenses which have genotypes pertinent to human lens diseases. These experiments compare the extrinsic stiffness of lenses from the genotype of interest to the wild-type lens in an effort to reach conclusions regarding the cellular or molecular basis of lens stiffening. However, these comparisons are confounded by alterations in lens size and geometry which invariably accompany these genetic manipulations. Here, we utilize manual lens compression to characterize the stiffness of a porcine lens and a murine lens. An inverse elastographic technique was then developed to estimate the intrinsic shear modulus of each lens as well as the elastic modulus of the lens capsule. The results were in good agreement with the previous literature values.
Highlights
The ocular lens is the pivotal tissue in accommodation — the primate eye's ability to alter its focal length.[1]
The lens was placed in lens culture medium 199
Since the reported value of for the porcine lens is 2.5–3.0 GPa,[46] the optimal value of G is e®ectively independent of as long as the /G ratio exceeds 100. This approach was previously adopted by Burd et al, whoxed the ratio of bulk modulus to shear modulus at 100 for all simulations.[8]
Summary
The ocular lens is the pivotal tissue in accommodation — the primate eye's ability to alter its focal length.[1] This process uses biomechanical deformation of the lens to achieve a change in optical power.[2] Presbyopia is the progressive loss of accommodation amplitude with age and appears to arise due to an alteration in the biomechanical. This is an Open Access article published by World Scientic Publishing Company. Further distribution of this work is permitted, provided the original work is properly cited
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