The surface of the eye--a superficial entity with deep repercussions

The surface of the eye is an anatomical and functional entity with a relatively recent delimitation but with significant therapeutic and diagnostic consequences. The pathology of the conjunctive and cornea must be approached by looking at the interrelations between the two tissues that are so different anatomically and functionally but in the same time form a unit in structuring the eye's surface. There are two major categories of relations between the two tissues: one of them is mediated by lachrymal secretion, a process whose complexity is not yet fully understood, and the other is germinal, referring to the stem cells located at the limbus which become epithelial cornea cells that can fixate lachrymal fluid. Imbalances in the quantity and quality of lachrymal secretion can be compensated, up to a certain point, by artificial products, but in severe cases only specially prepared autologous serum can compensate the deficit. The limbic deficits that affect stem cells require complex therapeutic procedures like limbic cell transplant, using an amniotic membrane or autologous serum.