Background: In our previous study, both allogeneic and xenogeneic smallincision
femtosecond laser-assisted intrastromal keratoplasty were demonstrated to be
safe and effective surgeries. Glycerol-dehydrated corneal lamellae could serve as
alternative xenogeneic inlay grafts. However, these xenogeneic lamellae have not been
explored in lamellar keratoplasty (LK). The immunoreactivity differences between
corneal intrastromal xenotransplantation and xenogeneic LK have not been assessed.
Methods: Rabbit lamellae were formed by femtosecond laser-assisted surgeries and
dehydrated in glycerol for 1 week at 4°C. The lamellae were used in two surgical
approaches in the small incision lenticule extraction (SMILE) group and the LK group.
Postoperatively, slit-lamp examinations, corneal topography, anterior segment optical
coherence tomography (AS-OCT), in vivo confocal microscopy and tear inflammatory
mediator assays were performed.
Results: Throughout the 12-month observation period, all rejection index ratings were
higher in the LK group than in the SMILE group. No signs of graft rejection were
observed in the SMILE group, but obvious neovascularization and corneal rejection
occurred in the LK group. Corneal topography showed that the anterior curvatures at the
central cornea and the mid-peripheral cornea were significantly increased in the SMILE
group but decreased in the LK group. All the grafts from both groups were clearly visible
on AS-OCT. In vivo confocal microscopy showed few dendritic cells in the subepithelial
region in the SMILE group. Numerous dendritic cells and inflammatory cells were
observed in the basal epithelium and stroma in the LK group. In the LK group, the levels
of TGF-β1, CD40, ICAM-1, CD14 and IL-10 changed more than those in the SMILE
group. The levels of VEGF were significantly elevated 1 month after surgery in the LK
Conclusion: Small-incision femtosecond laser-assisted intrastromal keratoplasty
minimized invasiveness and improved surgical efficiency. This small-incision
intrastromal keratoplasty technique is superior to LK in terms of xenogeneic lamellae
biocompatibility. Moreover, glycerol-dehydrated corneal lamellae might be a viable
xenogenic corneal inlay graft.