Flat sections for detailed endothelial pathology of corneal buttons

Flat-section en face preparations of corneal buttons obtained from penetrating keratoplasty may be used for a panoramic pathological examination of the endothelial layer and of the reactive cellular events occurring in other layers. These provide a valuable supplement to the more conventional cross (sagittal) sections. To demonstrate the principles and practical value of this two-plane sectioning method, we present histological examples of several pathological conditions of the cornea.