Figure 4. Histological results at 1 year. Histological corneal sections of treated animals (A–D) show an implanted corneal epithelium of a multilayer configuration with maturation from polygonal basal cells to flat superficial cells. Beneath the epithelium there is an acellular colagenous hyaline layer (arrows) with isolated keratocytes. The median and deep stroma as well as the Descemet membrane and endothelium have a normal appearance (hematoxylin and eosin stain; A). Periodic acid-Schiff  stain shows epithelial-like cells with clear cytoplasm at the basal layer of the corneal epithelium with a continuous basement membrane. A slightly periodic acid-Schiff positive acellular layer is seen between the epithelium and the normal corneal stroma (arrows; B). At the central area of the cornea, besides a thin homogenous layer beneath the epithelium, the remaining corneal stroma disclosed a normal lamellar configuration with interspread keratocytes (Masson stain; C). In the peripheral cornea, a thick layer of proliferated myofibroblasts and colagenous disposition deposits containing a few inflammatory cells is present between the implanted epithelium and the remaining corneal stroma (Masson stain; D). In the control group (E–H) an irregular regenerative epithelium from the limbal conjunctiva can be distinguished over the remaining stroma and a subepithelial scarring with inflammatory cells and neovascularization is present (Hematoxylin and eosin stain; E). A taller epithelium compared to normal/treated corneas is evident, with incomplete surface cell differentiation (Hematoxylin and eosin stain; F). Periodic acid-Schiff of the peripheral cornea discloses the presence of goblet cells within the corneal epithelium and a scarring of the underlying corneal stroma (G). Central cornea of a control eye shows a multilayered squamous-like corneal epithelium and a thick layer of active scar containing myofibroblasts, colagenous deposits, and inflammatory cells at the interface within the remaining corneal stroma (Masson stain; H).