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.
- ^ 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
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