The structure of the trabecular meshwork of the primate eye: A light and electron microscopic study with peroxidase

Abstract

The trabecular meshwork of the anterior chamber angle is composed of two regions. Adjacent to Schlemm's canal is the meshwork region which is formed by cells with interdigitating processes and large intercellular spaces containing collagen. Between this meshwork region and the anterior chamber is the trabecular region in which the cells closely envelop a collagenous core. The endothelium of Schlemm's canal is a complete, nonfenestrated membrane. Protrusions of meshwork tissue into Schlemm's canal form villi that are invested by the intact endothelium of Schlemm's canal. There are no canals, large pores, or other open channels of communication between the anterior chamber and Schlemm's canal. Peroxidase injected into the anterior chamber is trapped appreciably in the spaces of the trabecular meshwork. The connective tissue cells and infiltrating leukocytes become phagocytic, and within 4 days have disposed of the injected protein. No evidence was found for the direct passage of peroxidase into Schlemm's canal through endothelial cell vacuoles. The results of this study suggest that the anterior chamber and the spaces of the chamberangle connective tissue are structurally delimited from Schlemm's canal and that the trabecular meshwork may function as a biological filter.