Biomechanics of the Cornea and Sclera
(a) Schematic of our microscope-mounted mechanical
testing device enabling assessment of
the depth-dependent material properties of the cornea
(or sclera) under shear and compressive loading.
(b) Shear strain map across a button from
cornea sheared in the nasal-temporal direction. (Enlarged image)
Keratoconus, a vision-threatening degenerative disease of the cornea, is characterized by local changes in structure and composition that are accompanied by local changes in mechanical properties. Since the eye is a pressurized organ, these mechanical changes affect the shape and optical power of the cornea and can severely impair vision.
In collaboration with Dr. Yousuf Khalifa at Emory University, we are working to characterize the depth- and location-dependent material properties of the cornea in tension, compression and shear by combining simultaneous high-speed microscopy, force measurement and control of deformation on viable corneal explants. By correlating our data with structural and compositional data that can be obtained in vivo, we aim to enable novel clinical tools that can identify focal changes in corneal mechanics and thereby aid in the diagnosis and treatment of keratoconus and other diseases of the cornea. Similar studies are underway in the sclera, where local mechanical changes that alter the shape--and, in turn, the optics--of the pressurized eye could be key factors in the onset and progression of myopia.
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