Veterans at Risk The Health Effects of Mustard Gas and Lewisite (1993) / Chapter Skim
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8 Ocular Effects of Mustard Agents and Lewisite
8 Ocular Effects of Mustard Agents and Lewisite
Pages 131-147
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From page 131... ...
The lids also close to protect the eye, and in doing so they periodically replenish the tear film lost from evaporation and lacrimal drainage. Underlying the comeal epithelium is a specialized region of collagen tissue.
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From page 132... ...
The inner surface of the cornea is lined with a single layer of endothelium, a metabolically active cellular layer that pumps electrolytes, water, and metabolites out of the cornea. The corneal epithelium is derived from a specific group of stem cells, encircling the cornea, that multiply and ultimately form mature corneal cells.
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From page 133... ...
When doses exceed 200 mg mir~/m3, however, corneal edema or swelling occurs. At even higher doses, severe corneal damage takes place, with significant loss of vision (Papirmeister et al., 1991~.
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From page 134... ...
134 o .cn o V' V]
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From page 135... ...
· Immediate damage to the corneal epithelium, with edematous clouding and necrosis of the stroma. · After five hours, dense infiltration of polymorphonuclear neutrophils at the sclerocorneal junction, extending into the corneal stroma.
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From page 136... ...
136 I_ o ~ ~ — .° ~ ~ ·g o ._ = '- E ' .u ~ =' ~ ._ o hi, -8 ° .' to — ~ C ~ ~ ~ , ~ ~ ~ ·— ·— ~ _ ~ —' ~ ' ~ .
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From page 137... ...
Class III was subdivided into IIIa (mild corneal changes with a prognosis of return to active duty in six weeks to three months) and IIIb (severe corneal changes resulted in disability of more than three months)
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From page 138... ...
scars break down (delayed mustard gas keratitis)
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From page 139... ...
A summary of the toxic accidents in all three mustard gas production factories in England showed that 10.4 percent of 939 eye
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From page 140... ...
found only 2 patients in whom severe corneal ulceration developed; both cases ultimately recovered useful vision. Beauvieux also examined the retinal blood vessels and condition of the retina in 120 cases of severe generalized sulfur mustard lesions and noted venous dilatations in 34 percent and hyperemia of the optic disk in 23 percent.
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From page 141... ...
This might explain a report of progressive narrowing of the retinal blood vessels in a 34-year-old man who had sustained a relatively mild exposure to sulfur mustard in 1917 that nevertheless resulted in bilateral blindness (Oswald, 1920~. Chronic Course Many patients continue to have recurrent corneal erosions and inflammatory keratitis for an indefinite number of years after the serious corneal injury.
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From page 142... ...
This corresponds to Class III injuries in which there is (a) damage to the limbal blood supply, associated with moderate corneal edema, superficial collections of inflammatory cells, with or without superficial corneal vascularization; or (b)
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From page 143... ...
Ocular Epithelial Damage The most trying and difficult problems associated with mustard gas injuries are the corneal complications that can occur in the early, intermediate, but especially the late phases after exposure. Recent research suggests that the loss of ocular epithelium is a key factor in persistent epithelial defects of the cornea, giving rise to new disease entities called "ocular surface disease" and "stem cell disease." Even when the cornea itself has not been damaged, loss of stem cells can result in persistent epithelial defects that win encourage inflammatory cell invasion, vascularization, and scarring.
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From page 144... ...
Sulfur Mustard Compared to Alkali Injury: The Stromat Component Sulfur mustard injuries bear distinct similarities to alkali or very strong acid injuries of the eye. If these two injuries present similar problems, then treatments that have been initiated for alkali burns of the eye might well be effective in mustard gas or Lewisite injuries.
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From page 145... ...
1937. Delayed corneal ulceration following mustard gas burns.
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From page 146... ...
1944. A study of eighty-four cases of delayed mustard gas keratitis fitted with contact lenses.
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From page 147... ...
1945. Clinical and pathological studies of ocular mustard gas burns.
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