Cornea oedema

A passive flux of water continually flows across the endothelial layer toward the stroma, which has a tendency to swell. An active pump mechanism pulls an aqueous flux in the opposite direction which controls corneal turgescence [13]. Corneal deturgescence is an ATP-dependent process of the endothelial cells and as such any disruption of the endothelium may result in corneal oedema, thereby affecting corneal transparency. The specific distribution of different proteoglycans across the cornea has recently been implicated in water gradients across the cornea. This water gradient serves to diminish dehydration of the front of the cornea, which is exposed to the atmosphere. 

In the case illustrated, the caustic effect of the vapour is seen chiefly in the interpalpebral aperture. On each side of the cornea there is a dead white band due to coagulative oedema, which compresses the vessels, impairs the circulation, and thus acts as a menace to the nutrition of the cornea. The swelling in the region of this white band is slight, while the protected conjunctiva above and below it is greatly swollen and injected and may even bulge between the lids. 

No evidence of inflammatory response was observed in the rabbit cornea bioassay with any of the implants at any time. On average, the bulk of the polymers disappeared completely between 7 and 14 days after implantation (Rock et al., 1991). In similar animal experiments in which polyanhydride matrices containing tumour angiogenic factor (TAF) were implanted into rabbit cornea, a significant vascularisafion response was observed without oedema or white cells. Moreover, and most important from the biocompatibility standpoint, polymer matrices without incorporated TAF showed no adverse vascular response (Langer et al., 1981, 1985). 

WEL 8-hour TWA 25 ppm. Anhydrous ammonia has a corrosive action that will bum the skin, severely irritate or bum the cornea, cause bronchitis and pulmonary oedema. 

The main events occurring early in eye irritation involve the cornea and conjunctiva. In the case of the conjunctiva (Figure 3), inflammation is reflected by the onset of redness and chemosis. Microscopic examination shows the usual features of this inflammatory process, including cellular infiltration (monocytes and neutrophils), vasodilation and oedema of the connective tissue. It can also reveal fine alterations of cellular morphology with no clinical... 

Epithelial denudation and marked stromal oedema of cornea ... 

The conventional test for the irritant and corrosive potential of chemicals is the rabbit eye test, which was developed by Draize et al. (1944), and has become the international standard assay for acute eye irritation and corrosion (EC B.5, Directive 2004/73/EC OECD TG 405, 2002). The test material is applied to the conjunctival sac of the animal s eye and subsequent grading of ocular lesion is established cornea opacity, iris lesion, redness of conjunctivae, and oedema of conjunctivae (chemosis). 

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