Swiss researchers have published an online paper in Nature describing how adult stem cells in the cornea renew the transparent surface. The existence of stem cells in the eye and in the cornea has been know for some time. Most of the attention has focused on the limbus, the area at the outer rim of the cornea, as the source of stem cells for repair. This new work shows that the entire cornea contains stem cells that function in day-to-day repair of the cornea, and that the limbal stem cells are called into action when there is a more serious wound to the cornea that requires repair.

Transplants of limbal stem cells have been increasingly used to grow new corneas and restore sight in patients. The limbal stem cells can come from the patient's own eye or from a donor eye, and new corneas can actually be grown from cells taken from a patient's mouth.