Purpose: Previous studies have indicated that there are preformed channels at the inner aspect of the anterior sclera, capable of draining fluid from the suprachoroidal space into scleral veins. The aim of this study was to characterize the cellular lining of these channels, and to compare it with the endothelium of Schlemm's canal, the collector channels and the scleral blood vessels.
Methods: Histological sections from the angular region of human eyes were prepared by an immunoperoxidase method to evaluate the expression of factor VIII-related antigen in different aqueous drainage channels.
Results: The cellular lining of the scleral channels showed a weak immunostaining to factor VIII-related antigen. Factor VIII-related antigen was also detected in the endothelium of the collector channels and Schlemm's canal.
Conclusion: The positive immunoreaction to factor VIII-related antigen indicates that the previously described scleral channels, the collector channels and Schlemm's canal are all lined by an endothelium derived from a vascular origin.