Figure 6.

(a): Schematic of the 3D cartesian coordinate (X, Y, Z) and spherical coordinate $(\mathit{r},\mathit{\theta },\mathit{\phi })$ systems. (b): Illustration of the radial, meridional and circumferential directions for the ONH model in cut view (N-T direction) and anterior view. The radial direction was defined to be aligned with the through-thickness direction of the ONH, which agrees with the experimental data