Wound healing patterns following perforation sustained during laser in situ keratomileusis

Corneal perforation during laser in situ keratomileusis (LASIK) may interfere with flap adhesion and wound healing. The purpose of this study was to investigate wound healing patterns following corneal perforation sustained during LASIK in rabbits.

Forty-two pigmented rabbit eyes underwent LASIK surgery with 5.0-mm excimer laser treatment under the corneal flap. Animals were divided into two groups: group I (n = 19) underwent the regular LASIK procedure with -10.0 D treatment, without perforation; in group II (n = 23), the cornea was perforated with the excimer laser. Treatment was discontinued once perforation was observed, and the corneal flap was replaced without sutures. Slit-lamp biomicroscopy, photography, and scatterometry were performed preoperatively and at 1 and 2 days, 1 week, and weekly up to 1 month, 2 months, and 3 months postoperatively. Animals were killed at 1 day, 1 week, 1 month, and 3 months postoperatively and processed for light microscopic, electron microscopic, and immunohistochemical examinations.

In group I, the corneas remained clear throughout the experiment. In all eyes, the interface was not readily discernable clinically or histologically. Corneal wound healing was accompanied by minimal cell infiltration. Epithelial hyperplasia at the flap edge was noted at 1 week. Myofibroblast activation was found at the epithelial wedge where there was an epithelial basement membrane break. In group II, the anterior chamber was shallow with no iris incarceration at the end of surgery. The corneas were clear (n = 6) or showed mild to moderate edema (n = 12). Corneal edema peaked at 3.6 +/- 5.0 days and subsided thereafter. Corneal wounds healed similarly to those in group I except at the perforation site. The break in Descemet's membrane and endothelium was covered with a fibrin plug on day 1, which resolved thereafter. There was no statistically significant difference in the incidence of postoperative infection (p = 1.0) or flap displacement (p = 0.69) rates between the two treatment groups. The scatterometry index peaked at 2 to 3 weeks postoperatively and was significantly higher in group II than in group I (p < 0.001).

Although corneal perforation during LASIK surgery may interfere with immediate postoperative flap adhesion, corneal wound healing following LASIK perforation may be similar to that after an uncomplicated LASIK procedure.