An essential role of the cornea is to contribute to light focusing on the retina. Its curved shape, and therefore its ability to focus light, must be perfectly stable to ensure a sharp image despite the various shocks and rubs received over the course of a day. The cornea is thus composed of several hundred collagen lamellae stacked one on top of the other with various in-plane orientations.
Click here for original story, Mapping the lamellar structure of human corneas using polarization-resolved-SHG
Source: Phys.org