Early Corneal Wound Healing Response After Small Incision Lenticule Extraction.

Purpose: To evaluate the corneal wound healing response after small incision lenticule extraction surgery. Methods: Small incision lenticule extraction was performed in both eyes of 12 New Zealand White rabbits. The refractive spherical correction was set at -6.00 D. Two animals were analyzed at each time point (1 hour, 4 hours, 1 day, 3 days, 7 days, and 28 days). The corneas were evaluated using slit-lamp and in vivo confocal microscopy. After euthanatization, the corneal tissues were subjected to light microscopy, transferase 2'-Deoxyuridine 5'-Triphosphate (dUTP) nick end labeling assay, and immunofluorescence microscopy (CD11b, fibronectin, tenascin, alpha-smooth muscle actin [alpha-SMA]). Results: The corneas did not show any opacity at any time point except at the side-cut incision. By contrast, there was obvious scar tissue at the side-cut incision. Scattered, hyperreflective spots were seen by confocal microscopy from 1 hour postoperatively. Transferase dUTP nick end labeling-positive keratocytes were abundant near the femtosecond laser incision area at 1 hour and reached a peak at 4 hours postoperatively and then decreased. Inflammatory cells migrated from the incision into the central cornea, and this process began 1 hour after surgery and peaked at 7 days. Extracellular matrix components were deposited at the beginning of day 1 postoperatively, and the distribution pattern differed between the central cornea and the incision site. alpha-SMA-positive myofibroblasts were only detected at the side-cut incision. Conclusions: The scar tissue response in the peripheral cornea is related to the epithelium debridement. Inflammatory cells begin to be recruited by 1 hour after surgery. Therefore, it is necessary to implement antiinflammation interventions at a very early stage.