ABSTRACT
The Stem Cells of the Ocular Surface At least two major epithelial cell lines have been recognized on the ocular surface: corneal and conjunctival epithelia (Wei et al. 1993, 1996). The stem cells originating the corneal epithelium have been identifi ed at the corneosclero-conjunctival junction of the limbus (Schermer et al. 1986) thus referred as “limbal stem cells”. Conjunctival epithelial stem cells have been identifi ed at the mucocutaneous junction of the lid margins (Liu et al. 2007, Wirtschafter et al. 1997, 1999), the conjunctival fornix (Budak et al. 2005, Lavker et al. 1998, Pellegrini et al. 1999, Wei et al. 1995), the tarsal conjunctiva (Chen et al. 2003), and the bulbar conjunctiva (Nagasaki and Zhao 2005, Pellegrini et al. 1999) including the limbus (Pe’er et al. 1996). It is currently accepted that the conjunctival stem cells are dispersed all over the conjunctiva. Moreover, oligopotent stem cells capable of generating either conjunctival or corneal phenotypes depending on the environment have been found dispersed throughout the entire ocular surface including the cornea (Majo et al. 2008).
