Coagulation factor VIII. Localization in the aqueous outflow pathways.

Antihemophilic factor A-von Willebrand factor (AHF-vWF) is a protein involved in the first phase of blood coagulation and in the mechanism of platelet adhesion. The localization of this protein has been studied in the anterior segment of fetal and adult human eye by a direct immunofluorescence method. It was found that AHF-vWF is present in the wall of aqueous outflow pathways but not in that of Schlemm canal. As it has fibrinolytic activity in the endothelium of Schlemm canal, this structure can be expected to be especially well protected against fibrin deposition and occlusion by platelets and thrombi. The ciliary processes of the adult eye had no AHF-vWF activity. Instead, fluorescein isothiocyanate-fluorescence could be seen in the vessel wall of the ciliary processes of the fetal eye. This difference may be connected with the function of aqueous secretion.