The inflation response of the posterior bovine sclera

An in vitro inflation test method was developed to characterize the mechanical behavior of the bovine posterior sclera. The method used digital image correlation to provide a spatially resolved, full-field deformation map of the surface of the posterior sclera in response to controlled pressurization. A series of experiments were performed in the range of 2-6 kPa (15-45 mmHg) to characterize the load-unload displacement response at various pressure rates and the time-dependent displacement response at different applied pressures. The magnitude of the displacement was largest in the peripapillary region, mainly between the apex and the optic nerve head. Further, the results showed that bovine scleral tissue exhibited nonlinear and viscoelastic behavior characterized by a rate-dependent displacement response, hysteresis during unloading and creep. The creep rate was insensitive to the applied pressure, suggesting that the tissue can be modeled as a quasilinear viscoelastic material in the physiological pressure range of 2-6 kPa.