[Ultrastructure of collagen fibers in the sclera]

The Authors have studied the microfibrillar packing of the scleral collagen fibrils on thin sections of samples treated with a dissociant agent and on replicas of freeze-fractured fibrils. The only difference in observing the fibrils between the external and internal layers is relative to the diameter, evidencing in general, lower dimensions in the latter. The microfibrillar packing is characterized by a lightly spiralized or wavy running of filamentous subunits and the same is evident in fibrils of different diameter. The ultrastructural pictures are similar to those obtained in the other tissues, such as tendons, fibrous cartilages, fibrous capsules of parenchymatous organs and ligaments, in which the collagen is predominantly type I, like in the sclera.