Electron microscopic studies of epithelial adhesion complex of keratoconus

ABSTRACT

PURPOSE: Keratoconus is a bilateral noninflammatory ecstatic disease of cornea. Clinical manifestations and treatments are well-described , but the exact pathophysiology has many debates. There are many reports on pathologic abnormalities of keratoconus, but few reports on epithelial adhesion complex. The authors investigated the abnormalities in epithelial adhesion complex of keratoconus. METHODS: Using 4 corneas from 4 recipients of penetrating keratoplasty, examination was done with transmission electron microscope (Hitachi-600, Japan) after proper fixation and staining. Central and peripheral portion of each corneal tissues were examined. RESULTS: In two tissues, severe degeneration of basement membrane and Bowman's layer were found. Some degree of abnormalities was found in other tissues, which had minimal change. Some of hemidesmosomes, the most distinct part of adhesion complex, were found only in well-maintained tissue but the distribution was abnormal. CONCLUSIONS: The fact that basal plasma membrane had selectively more degenerations and changes than intercellular plasma membrane implies pathophysiology of keratoconus on adhesion complex, basal plasma membrane, basement membrane and Bowman's layer. Further study on this issue will reveal more information as to its pathophysiology.