The anatomy of the limbus.

The limbus forms the border between the transparent cornea and opaque sclera, contains the pathways of aqueous humour outflow, and is the site of surgical incisions for cataract and glaucoma. Externally the epithelial cell border between conjunctiva and cornea possesses multipotential cells important for differentiation of the respective cell types. By the same token, the internal limbal border zone between corneal endothelium and anterior trabeculum appears to contain specialised cells some of which are activated to migrate and repopulate the trabecular meshwork after trabecular injury. The oblique interface between corneal and scleral stroma determines the appearance of the surgical limbus whose landmarks vary around the circumference of the globe but predictably correlate with structures of the anterior chamber angle. The vasculature of the limbus derives in primates primarily from the anterior ciliary arteries. Their superficial branches form arcades to supply the limbal conjunctiva and peripheral cornea. Perforating branches contribute to the vascular supplies of the deep limbal structures and the anterior uvea.