Fig. 86. Alkali burn. A. Because of the lytic nature of an alkali injury, the central cornea has perforated, the iris and ciliary body are necrotic, and the lens is cataractous. (Hematoxylin-eosin stain; × 12.) B. At higher magnification, in the region of the necrotic cornea, the vacuolization of the extracellular material sensitive to proteolytic enzymes from polymorphonuclear leukocytes is evident. (Periodic acid-Schiff stain; × 16.)