[Pathology of the vitreous body. Primary aspects and principles].

Due to its simple structure, the vitreous body exhibits only a limited spectrum of pathological reactions. This structure undergoes age-related changes and degeneration throughout life. Modification in the relation between collagen and hyaluronic acid causes condensation of the vitreous fibrils, forming tractus, membranellae, and strands next to formations of clefts, lacunae, and detachments. Diseases of the adjacent tissues influence these degenerations qualitatively as well as quantitatively. According to its current condition, the vitreous body can influence the course and extent of diseases of adjacent tissues, its own structures acting as barriers or guiding formations for cells and tissues or as tracting "tendons". These basic principles are illustrated with examples from the particular pathology of the vitreous.