Fig. 2. Schematic diagram of vitreous collagen fibril organization (d'après Bishop62). The central core of vitreous collagen fibrils is composed of a hybrid of collagen types V and XI molecule. Surrounding the core is a specialized form of type II collagen, which constitutes 75% of vitreous collagen. N-propeptide extensions of these two components are found on the surface of vitreous collagen fibrils and may mediate interactions with other extracellular components of vitreous. However, the presence of type IX collagen on the surface of vitreous collagen fibrils probably plays a significant role in this regard.