The vertebrate corneal epithelium: from early specification to constant renewal.

BACKGROUND: The cornea is an ectodermal/neural crest derivative formed through a cascade of molecular mechanisms to give rise to the specific optical features necessary for its refractory function. Moreover, during cornea formation and maturation, epithelial stem cells are sequestered to ensure a constant source for renewal in the adult. RESULTS: Recent progress in the molecular and stem cell biology of corneal morphogenesis and renewal shows that it can serves as a paradigm for epithelial /mesenchymal organ biology. This review will synthesize historical knowledge together with recent data to present a consistent overview of cornea specification, formation, maturation, and maintenance. CONCLUSIONS: This should be of interest not only to developmental biologists but also ophthalmologists, as several human vision problems are known to be rooted in defects in corneal development.