[Pathologic, electron microscopic and experimental examination of band keratopathy]

One hundred and thirteen cases previously diagnosed as band keratopathy were reexamined by light microscopy and histochemistry, 10 cases of which were studied by TEM and 2 cases were studied by SEM. We find that the calcium deposition initially occur as fine calcific particles within the cytoplasm of epithelic cells and in the basal membrane and bowman's layer, which aggregated to form calcific spherules and large calcific masses extracellularly. When 3 normal corneal tissues were frozen and cultured, the calcium deposition occur in the superficial layer of bowman's membrane and in the stromal lamellae, Authors suggest that the degeneration and calcific abnormal metabolism of the cell caused by various factors is the main pathogenesis that leads to the calcific deposit. The evaporation and constructive destruction of the corneal surface in the interpiperbral area inhibits the formation of the lacrimal membrane and results in deposition of calcium salts in the superficial tissue of exposed cornea in a band configuration. The combination of glycosaminoglycan with calcium salts is the dynamics of aggregation of the fine calcific particles to form the calcific spherules and calcific masses.