Reassembly of the Corneal Epithelial Adhesion Structures Following Human Epikeratoplasty

Ten epikeratoplasty lenticules removed after surgery were obtained for immunohistochemical and electron microscopic analysis to determine the pattern of re-formation of corneal epithelial adhesion structures. Antibodies to laminin and type VII collagen were used to determine the presence of basement membrane and anchoring fibrils, respectively. Electron micrographs were used to determine the percentage of basal cell membrane occupied by hemidesmosomes, the area of basal lamina per 100 microns of basal cell membrane, and the average maximum depth of penetration of anchoring fibrils into the stoma. Nine normal corneas served as controls. Compared with normal corneas (24.5% of basal cell membrane occupied by hemidesmosomes; 32.0 microns 2 basal lamina per 100 microns of basal cell membrane), lenticules removed for optical reasons had near-normal hemidemosomes as early as 10 weeks following surgery (mean, 20.3%). The area of basement membrane was reduced (16 microns 2 basal lamina per 100 microns of basement cell membrane). During the course of 2 to 3 years, irregularities and duplications of the basement membrane were noted. Compared with normal corneas, the two lenticules removed for persistent defects had a marked reduction of hemidesmosomes and basement membrane present under epithelium at 3 and 4 weeks (9.6% of basal cell membrane occupied by hemidesmosomes and 13.6 microns 2 basal lamina per 100 microns of basal cell membrane, and 5.4% of basal cell membrane occupied by hemidesmosomes and 7.2 microns 2 basal lamina per 100 microns of basal cell membrane, respectively.