Fig. 3. Schematic diagram of the corneal wound healing process.

Corneal injury involving disruption to Bowman’s membrane results in the increased exposure of cytokines and growth factors including TGFβ and PDGF into the anterior stroma. TGFβ induces the normally quiescent keratocytes and/or bone-marrow derived cells to transdifferentiate into myofibroblasts to facilitate corneal repair. During physiological wound healing, myofibroblasts disappear by apoptosis and tissue transparency is maintained. However, in pathological conditions, myofibroblasts persist and secrete excessive amounts of aberrant extracellular matrix proteins (fibrosis) resulting in corneal scarring.