Authors: Nihar S Shah David C Beebe Spencer P Lake Benjamen A Filas
Publish Date: 2016/03/16
Volume: 44, Issue: 10, Pages: 3084-3095
Abstract
Although linked to several vitreoretinal pathologies including traumatic retinal tears breaks and symptomatic vitreomacular traction the dynamic material behavior of the vitreous body in response to mechanical loads is not well understood The purpose of this study was to evaluate spatiotemporal patterns of collagen fiber reorganization and vitreous deformation strain in response to tensile and compressive forces Using thick slabs of bovine eyes we examined collagen fiber reorganization following tensile and compressive steploading with quantitative polarized light imaging Strains were measured from sparse marker arrays and temporal collagen behavior was estimated from creep compliance rheological tests Results showed that under applied loads 1 collagen fibers became significantly more aligned at the vitreous base near the pars plana and the ciliary body 2 vitreous located directly behind the lens deformed significantly more than surrounding regions and 3 changes in collagen fiber alignment occurred on a short 5 s timescale Together these results show that despite a homogeneous visual appearance the vitreous body exhibits anisotropic material behavior in tension and compression Spatiotemporal patterns of collagen rearrangement were consistent with epidemiological patterns of traumatic retinal damage and vitreoretinal topology High strains in the vitreous corresponded with locations of lower collagen content that are prone to agerelated degeneration These data suggest that differential fiber alignment and mechanical deformation could contribute to the pathogenesis of these diseases Computational models that incorporate these experimental data will help improve our understanding of the biomechanical mechanisms that contribute to the pathogenesis of traumatic retinal damage vitreous degeneration and vitreoretinal diseaseThis work was supported by funding from a Washington University startup Bear Cup award BFDB NS was supported by fellowships from a Summer Students in Biomedical Research Award and through the Summer Research for Undergraduates program SL acknowledges support from the School of Engineering and Applied Sciences at Washington University We are grateful to Ruth Okamato PhD Mechanical Engineering Washington University for advice and training on the shear rheometer
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