Femtosecond Laser-assisted Endokeratophakia Using Allogeneic Corneal Lenticule in a Rabbit Model

To investigate the feasibility of allogeneic corneal lenticule implantation using the femtosecond laser as a method for cornea remodeling.

Small incision lenticule extraction was performed on the right eyes of 15 New Zealand white rabbits. Corneal intrastromal pockets were created with a femtosecond laser on the left eyes. Allogeneic corneal lenticule implantation was performed on the left eye immediately after the lenticule was extracted from the right eye. All animals had preoperative and postoperative slit-lamp photography, ultrasonic pachymetry, corneal endothelial cell count, anterior segment optical coherence tomography, in vivo confocal microscopy, and retinoscopy refraction during the observation period of 8 weeks. The rabbits were killed 8 weeks after surgery. Corneal wound healing response was analyzed by transmission electron microscopy, hematoxylin-eosin staining, TUNEL assay, and immunofluorescent staining.

Mild corneal edema and decreased clarity were noted the first few days after implantation, improving to normal 8 weeks after surgery. The corneal thickness and retinoscopy refraction were stable during the observation period. Viable keratocytes could be detected within the lenticule lamellae by ultrastructural analysis 8 weeks after surgery. The anterior and posterior border of the lenticule showed acellular layers with highly irregular collagen arrangement on transmission electron microscope images. Proliferating Ki-67 positive cells were present only in the epithelium layer.

Femtosecond laser-assisted endokeratophakia using allogeneic corneal lenticule may be feasible for reshaping cornea, providing a new possibility in refractive surgery and keratoconus treatment.