corneal stroma

(redirected from Substantia propria)

corneal stroma 

The thickest layer of the cornea located behind Bowman's layer and in front of Descemet's membrane. It represents approximately 90% of the total corneal thickness and gives the cornea its strength. The stroma consists of about 300 lamellae of parallel collagen fibrils in the centre of the cornea reaching to nearly 500 lamellae at the limbus. In between the fibrils are proteoglycans whose core proteins bind one with keratan sulfate and the other with dermatan sulfate (chondroitin sulfate B). The orientation of the alternate lamellae differs with each other, but they are all parallel with the corneal surface. In the central part of the cornea the majority of the collagen fibrils are orientated in the inferior-superior and nasal-temporal directions, whereas at the limbus they are orientated circumferentially, providing greater resistance to forces perpendicular to the axes of the fibrils. Between the lamellae are found the elongated flattened keratocytes (corneal corpuscles) from which the collagen fibrils are produced during development. When the cornea becomes oedematous due to trauma, disease or hypoxia, some of the fibrils lose their usual uniform calibre, become displaced and fluid accumulates between the lamellae, the stroma then loses its transparency. Syn. substantia propria.
References in periodicals archive ?
It represents melanocytes that migrate into the sclera, the episclera or the substantia propria but do not reach the epithelium.
As in the skin, most conjunctival nevi arising in adults show "maturation" with depth, that is, progressive evolution of the cell type from A to B to neurotized spindle C cells, with depth of the lesion into the superficial substantia propria.
10) These are more prevalent in the older age groups and have predominantly type B or C nevomelanocytes in the substantia propria, without an intraepithelial component.

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