Corneal and conjunctival epithelia arise from a common ancestral ectoderm cell, then diverge into distinct lineages. The former develops into a multilayered stratified squamous epithelium, the latter into an expansive mucous membrane that stretches the eyelid margin to the cornea's outskirts. The limbus, which intersects these epithelia, is purported to harbor corneal stem cells. Intrinsic programs that prevent these neighbouring epithelia from mixing and changing identity have not been elucidated, however microenvironmental cues that emanate following tissue damage and ensuing disease, dictate cell fate choices including those that influence form and function. Plasticity of ocular surface epithelia is gauged by their ability to undergo epithelial-mesenchymal transition, transdifferentiation, dedifferentiation and metaplastic transformation. Elucidating the molecular mechanism by which these rare and unusual phenomena arise, and persuading cells to either revert to their original state or remain newly committed, could be exploited into game-changing therapeutics for patients with corneal blindness and other diseases.

角膜和结膜上皮源自共同的祖先外胚层细胞，然后分化成不同的谱系。前者发育成多层鳞状上皮，后者发育成扩张的粘膜，将眼睑边缘延伸至角膜的外围。与这些上皮细胞相交的角膜缘据称含有角膜干细胞。阻止这些邻近上皮细胞混合和改变身份的内在程序尚未阐明，但是组织损伤和随之而来的疾病后发出的微环境线索决定了细胞命运的选择，包括影响形态和功能的选择。眼表面上皮的可塑性是通过其经历上皮-间质转化、转分化、去分化和化生转化的能力来衡量的。