corneal stroma

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 ?
Peters' anomaly is a rare congenital ocular anomaly caused by defective dysgenesis and cleavage of the anterior chamber of the eye causing central corneal opacity (leukoma), absence of the posterior corneal stroma and Descemet membrane, and a variable degree of iris and lenticular attachments to the central aspect of the posterior cornea (1).
The corneal stroma is endowed with a significant number of resident dendritic cells.
Highlights from the study observations include:Topically applied remlarsen penetrated into the cornea, without obvious local toxicity following corneal injury; Remlarsen treatment resulted in a decrease in corneal scarring and hazing as assessed by clinical evaluation and histopathology; Remlarsen treatment increased the corneal epithelial thickness, decreased the stromal thickness, and reduced the number of alpha-smooth muscle actin positive myofibroblasts in the corneal stroma; and Remlarsen treatment resulted in a reduction of pro-fibrotic gene expression from day 7-14 post-injury, indicating that target engagement was achieved in keratocytes and myofibroblasts in the corneal stroma.
Cornea endothelium is a monolayer of hexagonal cells forming the corneal inner surface, as well as the barrier between cornea and aqueous humor.[19] CECs pump water from corneal stroma to anterior chamber actively to maintain cornea's transparency and relative dehydration status and they do not divide after birth in vivo .
When the injury damaged only the ocular surface epithelium, including the limbus but sparing the corneal stroma, CLET was sufficient to restore corneal integrity and improve visual acuity; when the corneal stroma was involved by the injury, the corneal scarring required a subsequent keratoplasty for visual recovery [70] (Figure 4).
Young et al., "A selective inhibitor of the Rho kinase pathway, Y-27632, and its influence on wound healing in the corneal stroma," Molecular Vision, vol.
Keratoconus is characterized by progressive thinning of the corneal stroma leading to structural alteration of the tissue.
A central 7 mm round corneal deepithelialization for efficient penetration of riboflavin through exposed corneal stroma was performed with the help of sterile blunt spatula.
Spontaneous chronic corneal epithelial defects in people are associated with basement membrane dystrophy, whereas in dogs, stromal alterations likely have a crucial role in the disease, causing a failed union between the epithelial basement membrane and the anterior layers of the corneal stroma. (3,4,7) In dogs, SCCED is well described, and although similar diseases occur in cats and horses, the abnormality is not well characterized.
Nubile et al.17 in a prospective, non-comparative, interventional study evaluated the results of integration of amniotic membrane into corneal stroma. Out of the 22 patients with non-infectious corneal ulcers, successful incorporation was found in 20(90.9%).
An ophthalmic examination revealed a severely dry eye, a corneal ulcer, and an epithelial defect in both eyes; she received 0.05% topical cyclosporine two times a day, a topical steroid four times a day, and artificial teardrops four times a day in both eyes (Figure 1).Photophobia, blepharospasm, and thinning of the left corneal stroma were also observed.
The end result is a localized inflammatory response, leading to the enzymatic destruction of local cellular architecture; in particular, neutrophils and macrophages release collagenase and other proteases that destroy the corneal stroma [1].