Specular microscopy of living corneal endothelium. Normal endothelium is shown on the left. Note the hexagonal shape of the endothelial cells. The corneal endothelium of a patient with Fuchs endothelial corneal dystrophy is shown on the right. Demonstrated are polymegathism (larger cells), pleomorphism (variability in size and shape of cells), and dark areas of endothelial cell loss (guttae).