Xerophthalmia: Difference between revisions

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'''Xerophthalmia''' ([[Greek language|Greek]] for '''dry eyes''' from ''Ξηροφθαλμία'' = ξηρός (dry) + οφθαλμός (eye)) is a medical condition in which the [[eye]] fails to produce [[tears]]. It may be caused by a deficiency in [[vitamin A]] and is sometimes used to describe that lack, although there may be other causes.
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'''Xerophthalmia''' (Pronounced "zer-ōf-thal-meə". [[Greek language|Greek]] for '''dry eyes''' from ''Ξηροφθαλμία'' = ξηρός (dry) + οφθαλμός (eye)) is a medical condition in which the [[eye]] fails to produce [[tears]]. It may be caused by a deficiency in [[vitamin A]] and is sometimes used to describe that lack, although there may be other causes.
   
 
Xerophthalmia caused by a severe vitamin A deficiency is described by pathologic [[xerosis|dryness of the conjunctiva]] and cornea. The conjunctiva becomes dry, thick and wrinkled. If untreated, it can lead to corneal ulceration and ultimately in blindness as a result of corneal damage.
 
Xerophthalmia caused by a severe vitamin A deficiency is described by pathologic [[xerosis|dryness of the conjunctiva]] and cornea. The conjunctiva becomes dry, thick and wrinkled. If untreated, it can lead to corneal ulceration and ultimately in blindness as a result of corneal damage.

Revision as of 13:36, 10 June 2010

Xerophthalmia
Classification and external resources
Specialtyendocrinology
ICD-10E50.6-E50.7
ICD-9-CM264.6-264.7
DiseasesDB34035
Patient UKXerophthalmia
MeSHD014985

Xerophthalmia (Pronounced "zer-ōf-thal-meə". Greek for dry eyes from Ξηροφθαλμία = ξηρός (dry) + οφθαλμός (eye)) is a medical condition in which the eye fails to produce tears. It may be caused by a deficiency in vitamin A and is sometimes used to describe that lack, although there may be other causes.

Xerophthalmia caused by a severe vitamin A deficiency is described by pathologic dryness of the conjunctiva and cornea. The conjunctiva becomes dry, thick and wrinkled. If untreated, it can lead to corneal ulceration and ultimately in blindness as a result of corneal damage.

Xerophthalmia is a term that usually implies a destructive dryness of the conjunctival epithelium due to dietary vitamin A deficiency — a rare condition in developed countries, but still causing much damage in developing countries. Other forms of dry eye are associated with aging, poor lid closure, scarring from previous injury, or autoimmune diseases such as rheumatoid arthritis, and these can all cause chronic conjunctivitis. Radioiodine therapy can also induce xerophthalmia, often transiently, although in some patients late onset or persistent xerophthalmia has been observed [1].

The damage to the cornea in vitamin A associated xerophthalmia is quite different from damage to the retina at the back of the globe, a type of damage which can also be due to lack of vitamin A, but which is caused by lack of other forms of vitamin A which work in the visual system. Xerophthalmia from hypovitaminosis A is specifically due to lack of the hormone-like vitamin A metabolite retinoic acid, since (along with certain growth-stunting effects) the condition can be reversed in vitamin A deficient rats by retinoic acid supplementation (however the retinal damage continues). Since retinoic acid cannot be reduced to retinal or retinol, these effects on the cornea must be specific to retinoic acid. This is in keeping with retinoic acid's known requirement for good health in epithelial cells, such as those in the cornea.

Epidemiology and mechanical etiology

Xerophthalmia usually affects children under nine years old and "accounts for 20,000-100,000 new cases of childhood blindness each year in the developing countries." The disease is largely found in developing countries like many of those in Africa and Southern Asia. The condition is not congenital and develops over the course of a few months as the lacrimal glands fail to produce tears. Other conditions involved in the progression already stated include the appearance of Bitot's spots, which are clumps of keratin debris that build up inside the conjunctiva and night blindess, which precedes corneal ulceration and total blindness.

Treatment

Treatment can occur in two ways: treating symptoms and treating the deficiency. Treatment of symptoms usually includes use of artificial tears in the form of eye drops, increasing the humidity of the environment with humidifiers, and wearing wrap around glasses when outdoors. Treatment of the deficiency can be accomplished with a Vitamin A or multivitamin supplement or by eating foods rich in Vitamin A. Treatment with supplements and/or diet can be successful until the disease progresses as far as corneal ulceration, at which point only an extreme surgery can offer a chance of returning sight.

See also

References

  1. ^ Solans, R; Bosch, JA; Galofre, P; others (2001), "Salivary and lacrimal gland dysfunction (sicca syndrome) after radioiodine therapy.", Journal of Nuclear Medicine, 42 (5): 738–43, PMID 11337569

Notes

External links