Reassembly of corneal epithelial adhesion structures after excimer laser keratectomy in humans
T. R. Fountain, Z. de la Cruz, W. R. Green, W. J. Stark and D. T. Azar
Wilmer Ophthalmological Institute, Johns Hopkins Medical Institutions, Baltimore, Md.
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 microns
of basal cell membrane increased with the duration of wound healing (18.0
microns 2 at 6 months, 24.4 microns 2 at 15 months) but remained below
normal levels (32 microns 2). CONCLUSIONS: These data suggest that after
human excimer keratectomy, the anchoring fibrils and basal lamina do not
completely normalize even after 15 months.
