Abstract
Abstract: :
Purpose: To compare the effect on histological ultra structure of mechanical vs. alcohol-assisted excision of epithelial disks obtained by human corneas. Methods: 14 eyes of 14 patients underwent deepithelization with two different techniques: With the use of the prototype device (Duckworth and Kent, England) the epithelial layer was mechanically separated in 8 eyes. Among these 8 separated epithelial disks, seven were obtained for histological evaluation and one was replaced on the stroma after the ablation was performed and was removed one day postoperatively for histological assessment. The epithelial disks from the rest of the 14 eyes (6 eyes) were obtained with the conventional LASEK technique (used alcohol concentrations of 15% and 20%). All specimens were assessed with light and electron microscopy and histological findings were compared. Results: Transmission electron microscopy of the specimens showed that mechanical separation excised epithelial disks preserving the lamina densa and the lamina lucida as well as hemidesmosomes that demonstrated normal morphology almost along the whole length of basement membrane. Basal epithelial cells of the separated epithelial disks showed minimal trauma and edema. Specimens obtained using both 15% and 20% alcohol concentrations showed formation of cytoplasmic fragments of the basal epithelial cells, enlargement of the intercellular spaces and extensive discontinuities of the basement membrane, being excised at the level of lamina lucida. Light and transmission microscopy of the specimen that was removed one day postoperatively showed a high percentage of viable epithelial cells. Conclusions: Mechanical separation doesn’t affect the normal cell morphology in the excised epithelial disks. Transmission electron microscopy of the examined specimens proved this modality less invasive to the epithelial integrity as compared to the use of two different alcohol concentrations.
Keywords: cornea: epithelium