Reassembly of Corneal Epithelial Adhesion Structures After Excimer Laser Keratectomy in Humans

Objective: To determine the pattern of long-term reformation of the adhesion structures after excimer laser phototherapeutic keratectomy. Methods: Four corneal buttons were removed at penetrating keratoplasty 6 to 15 months after initial excimer laser phototherapeutic keratectomy. Morphometric analysis of electron micrographs of the wound bed was performed to determine the extent and pattern of reformation of hemidesmosomes, anchoring fibrils, and basal laminae. Results: Eight percent of the basal epithelial cells had underlying normal anchoring fibrils at 6 months, compared with 35% at 15 months. The percentage of basal cell membrane occupied by hemidesmosomes remained fairly constant (35.2% to 37.7%). With the exception of a localized area of multilamination seen at 9 months, the cross-sectional area of basal lamina per 100 μm of basal cell membrane increased with the duration of wound healing (18.0 μm₂ at 6 months, 24.4 μm₂ at 15 months) but remained below normal levels (32 μm₂). Conclusions: These data suggest that after human excimer keratectomy, the anchoring fibrils and basal lamina do not completely normalize even after 15 months.