Early Biocompatibility Following Xenogeneic Intrastromal Implantation of Excimer Laser–Reshaped Micro-concave Lenticules Derived From Human KLEx

PURPOSE: To investigate the early biocompatibility of excimer laser-reshaped micro-concave lenticules derived from human keratorefractive lenticule extraction (KLEx) following xenogeneic interlamellar implantation into rabbit corneas, and to evaluate the safety and feasibility of intrastromal implantation in vivo. METHODS: Twenty healthy New Zealand white rabbits were randomly assigned into two groups: the lenticule implantation group (n = 10) and the corneal intrastromal pocket group (n = 10). Human corneal intrastromal micro-convex lenticules derived during KLEx surgery were reshaped into micro-concave lenticules using an excimer laser and subsequently implanted into the corneal intrastromal layer of the rabbits. Slit-lamp microscopy was performed on postoperative days 1, 3, 7, 15, and 30. Anterior segment optical coherence tomography was conducted at 1 week and 1 month postoperatively. At the same time, five rabbits from each group were randomly killed and their corneas were harvested for hematoxylin-eosin staining, transmission electron microscopy, and immunohistochemical analysis. RESULTS: Mild corneal edema was observed during the first postoperative week and gradually subsided. No signs of complications were detected throughout the 1-month follow-up period. The interface between the implanted lenticule and the host corneal stroma remained visible. The collagen fibers within the implanted lenticules appeared relatively disorganized compared to those in the host cornea at 1 week postoperatively. By 1 month, they became more regular, resembling the recipient cornea. No detectable infiltration of CD4+ or CD8+ T cells was observed. CONCLUSIONS: Excimer laser-reshaped human corneal intrastromal micro-concave lenticules exhibited favorable early biocompatibility and structural stability following xenogeneic intrastromal implantation in rabbit corneas.