Poster abstracts
Poster number 18 submitted by Matthew Reilly
Molecular Contributions to Lens Biomechanical Properties
Matthew A. Reilly (Biomedical Engineering)
Abstract:
Presbyopia - the age-related loss of near vision - is associated with massive changes in stiffness of the nucleus of the ocular lens. This stiffening prevents the lens from changing shape and therefore changing its optical power. However, the molecular mechanisms governing this stiffening remain unknown. In this study, we employed a combination of molecular techniques to characterize the lens' soluble proteins. These highly concentrated (up to 600 mg/mL) proteins give the lens its high refractive index while contributing only a negligible amount to its elasticity in youth. However, these proteins are not renewed and remain throughout life, accumulating modifications arising from exposure to oxidative stress, ultraviolet light, and other factors. We hypothesize that these modifications result in protein aggregation and ultimately gelation. We combine Raman spectroscopy, dynamic light scattering, and dynamic shear rheometry to characterize the behavior of lens soluble protein solutions under various conditions which mimic specific aspects of the aging process, providing insights into how these molecular-level changes contribute to changes in macroscopic biomechanical properties and, therefore, the loss of near vision. We also characterize intact lenses using a variety of biomechanical tests. These experiments are supported by various physical and chemical computational models to maximize the insights gained.
Keywords: presbyopia, biomechanics, computational modeling