Observation on ultrastructure and histopathology of cornea following femtosecond laser-assisted deep lamellar keratoplasty for acute corneal alkaline burns

AIM： To demonstrate the changes in ultrastructure and histopathology of the cornea in acute corneal alkaline burns after femtosecond laser-assisted deep lamellar keratoplasty.·METHODS： The New Zealand white rabbits treated with alkaline corneal burn were randomized into two groups,Group A（16 eyes） with femtosecond laser-assisted deep lamellar keratoplasty 24 h after burn and Group B（16 eyes）without keratoplasty as controls. All eyes were evaluated with transmission electron microscopy（TEM） at 1, 2, 3,and 4wk follow-up, then all corneas were tested by hematoxylin and eosin staining histology.· RESULTS： The corneal grafts in Group A were transparent, while those in Group B showed corneal stromal edema and loosely arranged collagen fibers. One week after treatment, TEM revealed the intercellular desmosomes in the epithelial layers and intact non-dissolving nuclei in Group A. At week 4, the center of the corneas in Group A was transparent with regularly arranged collagen fibers and fibroblasts in the stroma. In Group B, squamous cells were observed on the corneal surface and some epithelial cells were detached.· CONCLUSION： Femtosecond laser-assisted deep lamellar keratoplasty can suppress inflammatory responses, prevent toxic substance-induced injury to the corneal endothelium and inner tissues with quicker recovery and better visual outcomes.