Corneal Lenticule Allotransplantation After Femtosecond Laser Small Incision Lenticule Extraction in Rabbits.

PURPOSE: To investigate the feasibility of allotransplanting extracted lenticules after femtosecond laser-assisted small incision lenticule extraction (SMILE) in rabbits and the subsequent healing process.

METHODS: Fourteen New Zealand white rabbits were divided evenly into 2 groups. The rabbits in group A received SMILE procedures with a -6.00 D correction. The lenticules from group A were immediately inserted into a femtosecond laser-created corneal stromal pocket in group B. After surgery, the anterior segment was assessed in vivo by slit-lamp microscopy, corneal topography, optical coherence tomography, and confocal microscopy. All eyes were enucleated for hematoxylin-eosin staining and transmission electron microscopy after the animals were killed.

RESULTS: At postoperative day 1, there was moderate corneal edema in the implanted lenticule stroma. At 6 months, the lenticules were integrated with the surrounding tissue, and the boundary could not be identified through slit-lamp microscopy; regenerated branches of the corneal nerves were thicker than at postoperative month 1 as observed through confocal microscopy. The central corneal thickness increased by 58.75 ± 21.58 μm. The lenticules were gradually integrated with the surrounding tissue, and their density was similar to the adjacent tissue according to optical coherence tomography; however, a clear boundary between the lenticule and surrounding tissue was detectable using light microscopy and transmission electron microscopy, revealing disordered fibers and decreased keratocytes in implanted lenticules.

CONCLUSIONS: In this model it is feasible and safe to allotransplant extracted corneal lenticules after SMILE. Healing of implanted lenticules after SMILE is stable at postoperative 6 months, but collagen fiber rearrangement requires further investigation.