Fig. 7.

Sensitivity of lamina and sclera strains to the stiffness of the collagen fibers. Note that strains and modulus are both plotted using non-linear scales. The stiffness of the collagen fibers was varied over two orders of magnitude. The black dotted lines denote the baseline conditions. A line with zero slope indicates that the strain was insensitive to the stiffness of the fibers. Increasing the fiber stiffness in the model with circumferential fibers reduced the strains in the lamina but not the sclera. Increasing the fiber stiffness in the model with radial fibers did little to change the strains in the lamina and sclera. In the case of a combination of radial and circumferential fibers, increasing fiber stiffness resulted in small reductions in both lamina and scleral strains, although these changes were not in direct 1 to 1 proportion to the increase in stiffness. For the tangential fibers, lamina and scleral strains were reduced almost in direct proportion to the increase in stiffness. Note that both the sclera and lamina strains in the tangential fiber model with a modulus of 0.25 MPa were an order of magnitude smaller than the strains in the circumferential models with 50 MPa fibers.