On corneal transparency and its loss with swelling.

The cornea is the clear front covering of the eye through which we see and is composed of collagen fibrils embedded in an optically homogeneous ground substance. It has long been recognized that these fibrils scatter light and that transparency results from interference effects due to an ordering in the spatial arrangement of the fibrils about one another. The nature of this ordering and of its disruption in abnormal corneas is of great current interest. The present study reviews experimental light scattering and electron microscopic evidence relevant to this problem. This evidence suggests that theoretical attempts to model and understand corneal transparency and its loss during swelling, in terms of ultrastructure, must account for a short-ranged ordering of fibrils in normal healthy corneas and for the formation of regions void of fibrils in swollen corneas.