Woodruff School of Mechanical Engineering
COE/Structural Mechanics Seminar
The Biomechanics of the connective tissue of the eye-wall
Dr. Thao Nguyen
Johns Hopkins University
Thursday, April 16, 2015 at 1:00:00 PM
Love Building, Room 109
Dr. H. Jerry Qi
The connective tissues of the eye wall include the transparent cornea, stiff sclera, and lamina cribrosa of the optic nerve head. The mechanical properties of the connective tissues arise from the fiber-reinforce microstructure of the extracellular matrix, which is composed mainly of collagen and elastin fibers arranged in a proteoglycan-rich matrix. The mechanical behavior of the tissues is vitally important to their visual function. The shape of the cornea provides 75% of the un-accommodated refractive power of the eye. The shape of the sclera determines the position of the retina relative to the focal plane of the eye. The trabecular structure of the lamina cribrosa mechanically supports the retinal ganglion cell axons as they exit the eye. The tissue structures have different geometries and material properties, and the fibrous microstructure of the tissues have evolved to provide mechanical reinforcements at the junction of the dissimilar tissues. The tissues are also dynamic in that they experience growth and remodeling with age and with diseases. We have developed inflation experiments that use a variety of full-field deformation mapping methods to measure the mechanical behavior of the cornea, sclera, and lamina cribrosa. In addition, we have developed models for the mechanical behavior of the connective tissues that explicitly describe the anisotropic fiber structure. In this presentation, I will describe the integration of these methods study the relationship between the collagen structure and mechanical properties of the connective tissues of the eye-wall, and their alterations with age and glaucoma.
Thao Nguyen is an Associate Professor in the departments of Mechanical Engineering and Materials Science at The Johns Hopkins University. Dr. Nguyen obtained her S.B. in Mechanical Engineering from MIT in 1998, and M.S. and Ph.D. in Mechanical Engineering from Stanford in 2004. She worked as a research scientist at Sandia National Laboratories in Livermore, CA, before joining Johns Hopkins in 2007. Her research focuses on the biomechanics of soft tissues and mechanics of stimuli-responsive polymers. Dr. Nguyen was awarded the 2008 Presidential Early Career Award for Scientists and Engineers (PECASE) for her work on constitutive modeling of shape memory polymers. She has also received a 2013 NSF CAREER Award to investigate growth and remodeling of collagenous tissues, the 2013 UH Eshelby Mechanics Award for Young Faculty, the 2013 Sia Nemat-Nasser Early Career Award from the Materials Division of ASME, and the 2015 Thomas. J. R. Hughes Young Investigator Award from the Applied Mechanics Division of ASME.
Refreshments will be served.