[Lymph drainage of the cornea, limbus and conjunctiva]

Air (n = 30), patent blue (n = 30), Berlin blue (n = 30), Berlin blue and air (n = 30), and Berlin blue and Mercox (n = 30) were injected into the corneas and conjunctivas of 150 enucleated cattle eyes. Using air for injection, so-called Bowman "corneal tubes" form in the cornea, which can easily be filled with pigment (patent blue, Berlin blue). In some cases (n = 3) the conjunctival lymphatics were filled with air during injection into the cornea. Besides the "corneal tubes", larger vessel-like structures can be demonstrated, which seem to be connected to corneal nerves. The significance of these structures as prelymphatics and their importance in the lymph drainage of the cornea are discussed. The injection of patent blue and Berlin blue into the limbus leads to the formation of a delicate network of arch-shaped lymphatics, from which larger lymphatics take their color. In the case of Berlin blue and Mercox, and Berlin blue and air injection, sections of lymphatic vessels in the shape of pointed arches form at the edges of the segments. It can be shown stereomicroscopically that these are not valves or invaginations, but only hump-shaped diverticula of the vessels. Annular constrictions of the lymphatic vessels were found, rather than bicuspid valves. The valveless pump mechanism described by Liebau is discussed as a possible means of lymph transport in the conjunctiva.