Ocular surface stem cells and disease: current concepts and clinical applications.

Corneal and conjunctival epithelial stem cells are responsible for the homeostasis and regeneration of the ocular surface epithelium. Corneal epithelial stem cells reside in the basal region of the limbus, while the conjunctival forniceal region appears to be the site that is enriched in conjunctival stem cells. Ocular surface disease arising from limbal stem cell deficiency is characterised by persistent epithelial defects, corneal vascularisation, chronic inflammation, scarring and conjunctivalisation, resulting in visual loss. Limbal stem cell transplantation replaces the corneal stem cell population in these eyes with the hope of restoring vision. More recently, the use of bioengineered ocular surface tissue-equivalents has had promising results, and may represent the future for replacement and regeneration of ocular tissues in various ocular disorders.