Xerophthalmia
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| Xerophthalmia | |
|---|---|
| Classification and external resources | |
| ICD-10 | E50.6-E50.7 |
| ICD-9 | 264.6-264.7 |
| DiseasesDB | 34035 |
| MeSH | D014985 |
Xerophthalmia (Greek for dry eyes) 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.
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].
Xerophthalmia is due to lack of the vitamin A metabolite retinoic acid, since (along with growth-stunting effects) it can be reversed in vitamin A deficient rats by retinoic acid supplementation. Since retinoic acid cannot be reduced to retinal or retinol, these effects must be specific to retinoic acid.
[edit] Notes
- ^ Solans, R; JA Bosch & P Galofre et al. (2001), "Salivary and lacrimal gland dysfunction (sicca syndrome) after radioiodine therapy.", Journal of Nuclear Medicine 42 (5): 738-43, PMID 11337569
2. Medicine.Net. "Definition of Xerophthalmia." 26 May 2003.
<http://www.medterms.com/script/main/art.asp?articlekey=6040>.
3. Journal of Tropical Pediatrics "Xerophthalmia: A World-wide Drive for Prevention." 4 November 2009.
<http://tropej.oxfordjournals.org/cgi/pdf_extract/26/4/131>.
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 conjuctiva and night blindess, which precedes corneal ulceration and total blindness.
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.
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