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Keratomalacia
Keratomalacia is an eye disorder that results from vitamin A deficiency. Vitamin A is required to maintain specialized epithelia (such as in the cornea and conjunctiva). The precise mechanism is still not known, but vitamin A is necessary for the maintenance of the specialized epithelial surfaces of the body. A lack of vitamin A leads to atrophic changes in the normal mucosal surface, with loss of goblet cells, and replacement of the normal epithelium by an inappropriate keratinized stratified squamous epithelium. In addition, the substantia propria of the cornea breaks down and liquefies, resulting in keratomalacia. The resulting cornea becomes totally opaque, which is one of the most common reasons for blindness around the world, particularly in developing countries. See also * Acute promyelocytic leukemia * Keratoconjunctivitis sicca * Xerophthalmia Xerophthalmia (from Ancient Greek "xērós" (ξηρός) meaning "dry" and "ophthalmos" (οφθαλμός) meaning "eye") i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Xerophthalmia
Xerophthalmia (from Ancient Greek "xērós" (ξηρός) meaning "dry" and "ophthalmos" (οφθαλμός) meaning "eye") is a medical condition in which the eye fails to produce tears. It may be caused by vitamin A deficiency, which is sometimes used to describe that condition, 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. The first symptom is poor vision at night. If untreated, xerophthalmia can lead to dry eye syndrome, corneal ulceration, and ultimately to blindness as a result of corneal and retinal damage. Xerophthalmia 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 a previous inj ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |