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Abstract
The structure of the anterior chamber angle of primate eyes (man and rhesus monkey) was examined by methods of light and electron microscopy. The anatomic observations indicated that the trabecular meshwork could be clearly and simply divided into two parts by an imaginary line drawn from the region of the scleral roll to the end of Descemet's membrane (Schwalbe's line). The outer layers may be termed the corneoscleral; the inner layers, the uveal. The corneoscleral layers are further subdivided into two parts: a small narrow band of tissue lying adjacent to the inner wall of Schlemm's canal, the fuxtacanalicular connective tissue, and a much larger portion, the remainder of the corneoscleral meshwork. Physiologic experiments were carried out in young rhesus monkey eyes by using coarse tracers (India ink) for light microscopy and fine tracers (ferritin molecules) for electron microscopy. The ferritin molecules were found to pass through the fuxtacanalicular connective tissue layer to reach the endothelial lining of Schlemm's canal. These endothelial cells took up a number of the ferritin molecules, many within small vesicles, and transported them across the cell cytoplasm, discharging the molecules into the lumen of the canal. Ferritin molecules were also observed to pass in similar fashion into the capillaries of the ciliary muscle and iris root. All of the observations made in this study support a simplified histologic terminology for this regionmore in conformity with function than terms in current use. Histologic examination of cases of chronic open-angle glaucomaled to the development of a concept of the pathogenesis of chronic simple ("primary" open-angle) glaucoma. Thechanges are considered to be aging processes ivithin these tissues of the drainage angle, which hamper aqueous flow from reaching the lumens of these outflow vessels.