Measurements of the compressive properties of scleral tissue

Tests were conducted on small samples of sclera taken from cattle eyes and human eyes to determine the mechanical properties of the tissue in compression. It was found that the elastic modulus for radial compressive stress of human sclera was more than a factor of 100 less than the modulus for circumferential tensile stress. The stress-strain relationship was found to be mildly nonlinear and exhibited hysteresis when cycled through a pattern of increasing-then-decreasing stress. Given sufficient time, however, the sample returned to its original state and, therefore, exhibited no permanent deformation. Measurements of Poisson's ratio yielded values of 0.46 to 0.50, indicating that these samples were essentially incompressible.