This study investigated the 3-dimensional inflation response of intact bovine sclera to pressure-controlled load-unload and creep tests. The purpose of this study was to develop a methodology that captured the full 3-D displacement field of the scleral surface during inflation using a two-camera DIC method. The preliminary results give evidence of a time-dependent inflation response of the tissue with hysteresis measured in the load-unload tests and creep measured in the ramp-hold tests. The 3-D results also verify that the ONH and peripapillary regions dominate the deformation of the scleral shell. Additional samples will be tested to increase the statistical significance of the mechanical response findings, and thickness measurements will be taken before and after tests at multiple locations. First, however, i improvements to the experimental method will be implemented to control hydration, to image the ONH and peripapillary regions aligned with the optical axis, and to control the pressure loading rate. The goal of this research is to develop a robust inflation test protocol to characterize the physiological mechanical response of the sclera. The data will be used to fit a micro-structurally inspired viscoelastic constitutive model [7] to the tissue's inflation response to generate representative material properties. In the future, the methods will be applied to normal and glaucoma human sclera to identify biomechanical differences.
展开▼
