Abstract
Purpose::
To assess histological integrity and cell viability in epithelial flaps prepared with epi-keratomes.
Methods::
Epithelial flaps were prepared by epi-LASIK surgery for 23 cases of myopia (using redundant portions of reaffixed epithelial flaps) and by epi-PTK surgery for 18 cases of granular corneal dystrophy. After immediate fixation, the flaps were examined by light- and electron microscopy. To assess cell viability in fresh epithelial flaps, biostaining experiments were performed using propidium iodide (PI), calcein-AM, and Hoechst 33342 dye, followed by examination with confocal microscopy. In addition, some epithelial flaps were organ-cultured for 24 hours.
Results::
Light- and electron microscopically, most of the inspected areas exhibited nuclei and cytoplasm at significantly reduced densities and a discontinuity of the basement membrane. Biostaining experiments demonstrated that approximately 90% of the basal cells in the epithelial flaps were PI-positive dead cells; organ-cultures showed detachment of basal cells from the epithelial flap after 24 hours of incubation. Through biostaining, irregular basal cell layers were observed in epithelial flaps of granular corneal dystrophy.
Conclusions::
Most of the basal cells in epithelial flaps prepared with different epi-keratome devices were dead.This research was supported by Grant-in-Aid (18591931) for scientific research from the Ministry of Education, Science, Culture, and Sports of Japan.
Keywords: cornea: epithelium • refractive surgery • microscopy: confocal/tunneling