Collagen fibrils as skeletal frame in monkey trabecular meshwork.

In an attempt to identify the characteristic skeletal frame of the trabecular meshwork, the three-dimensional architecture of collagen fibrillar bundles (collagen bundles) was studied by applying the NaOH cell-maceration method to the anterior segment of cynomolgus monkey eyes. Collagen bundles in the trabecular meshwork were found to be continuous with thinner collagen lamellae in the peripheral cornea and with the collagen fibril plexus in the ciliary body. The collagen core in the uveal cord was columnar in shape and was arranged parallel to the long axis. Collagen bundles were arranged as the layered network forming the fundamental framework of the trabecular meshwork. Most collagen bundles of the corneoscleral sheet were arranged circularly, parallel to the circumference of the limbus, and numerous slender bundles were observed side by side, forming the flat and membranous configuration of the sheet. The endothelial meshwork consisted of a network of fine and sparse collagen fibrils forming extracellular spaces and intercommunicating openings. The inner wall of the canal of Schlemm was seen as a netlike surface of sparse collagen fibrils with variously sized circular openings. The openings suggested the possibility that development of giant vacuoles corresponds to the circular openings under the inner endothelial cell lining.