Corneal Epithelial Separation and Corneal Wound Healing Effect between Alcohol and Mechanical Device for Epithelial Flap

ABSTRACT

PURPOSE: Laser epithelial keratomileusis (LASEK) is a refractive surgery technique in which the cornea is covered with the epithelial flap after keratectomy. However, there have been reports of tissue damage by the alcohol utilized in this procedure while preparing the epithelial flap, which has led to novel methods. One of these is the mechanical designing of the epithelial flap named epipolis laser assisted in situ keratomileusis (Epi-LASIK). This study evaluates the histologic features and wound healing process of the corneal flap using Epi-Tome, which is the epithelial cutter of the newly introduced Epi-Lasik. METHODS: Twenty-four eyes of 12 dogs were devided into two groups. In one group (n=12), 20% alcohol was used and, in the other group (n=12), Epi-Tome (Gebauer, Germany) was used to make a corneal flap. The size change of a fluorescein-stained epithelial defect was followed postoperatively at 6, 12, 24, and 36 hours. RESULTS: The maximum decrease in defect size were observed at 0 to 6 hours in the Epi-Tome group, and from 6 to 12 hours in the alcohol group; the value were 10.01+/-5.32 mm2 and 9.23+/-4.75 mm2 respectively. Histologic review revealed that there was less tissue damage and smoother cut edge in the Epi-Tome group compared to the alcohol group, and the adhesion between stroma and epithelium was faster in the Epi-Tome group. CONCLUSIONS: Mechanically detached corneal flaps had favorable chances of survival such that re-epithelialization occurred early in the postoperative phase. A few epithelial fragments at a corneal section plane prevent corneal opacification and minimize inflammatory reaction, thus reducing postoperative pain.