The epithelium and stroma of experimentally alkali-burned corneas were studied by electron microscopy. In the ulcerating corneas, the number of basal epithelial cells increased at the edge of the regenerating epithelium. These corneas had no basement membrane, and many cytoplasmic processes protruded into the stroma. Some of the cytoplasmic processes contained vesicles, and many similar vesicles were found in the superficial stroma around these processes. In the ulcerated stroma, collagen fibers of the most superficial lamellae changed into fine fibrils and were continuous with an exudative mass. The nonulcerated cornea did not show these abnormalities.
These observations suggest that basal cells in the regenerating epithelium secrete some substances into the stroma, which may be responsible for, or related to, ulcer formation in the alkali-burned corneas.
Matsuda H, Smelser GK. Epithelium and Stroma in Alkali-Burned Corneas. Arch Ophthalmol. 1973;89(5):396-401. doi:10.1001/archopht.1973.01000040398009