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i came across this word in a food and nutrition grade 12 exam paper.

2006-11-13 20:31:10 · 0 answers · asked by ladymonze 1 in Health Diseases & Conditions Other - Diseases

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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 is a term that usually implies a destructive dryness of the conjunctival epithelium due to dietary vitamin A deficiency—a condition virtually forgotten 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.

Xerophthalmia can be associated with systemic diseases such as Sjögren's syndrome, systemic lupus erythematosus, rheumatoid arthritis, scleroderma, sarcoidosis, amyloidosis, and hypothyroidism; deficiency of vitamin A; and the use of some medications including antihistamines, nasal decongestants, tranquilizers, and anti-depressant drugs. Xerophthalmia results from inadequate function of the lacrimal glands which produce tears. When xerophthalmia is due to vitamin A deficiency, the condition begins with night blindness and conjunctival xerosis (dryness of the eye membranes) and progresses to corneal xerosis (dryness of the cornea), and, in the late stages, to keratomalacia (softening of the cornea).

The treatment depends on the cause. Artificial tears, which lubricate the eye, are the principal symptomatic treatment for dry eye. They are available over-the-counter as eye drops. Using humidifiers, wearing wrap-around glasses when outside, and avoiding outside windy and dry conditions may bring relief. For people with severe cases of dry eye, temporary or permanent closure of the tear drain (small openings at the inner corner of the eyelids where tears drain from the eye) may be helpful. Also known as conjunctivitis arida.

2006-11-13 20:41:36 · answer #1 · answered by mallimalar_2000 7 · 2 0

Xerophthalmia Symptoms

2016-12-28 15:37:38 · answer #2 · answered by brustrom 4 · 0 0

What Is Xerophthalmia

2016-10-03 03:59:20 · answer #3 · answered by ? 4 · 0 0

Dry eyes. "xero" comes from the Greek word for "dry". "Opthal" in any word means eyes.

itchiness, pain, blood shot eyes. scratchy feeling.

2006-11-13 22:40:14 · answer #4 · answered by P-nuts and Hair-dos 7 · 2 0

For the best answers, search on this site https://shorturl.im/ayj7R

Vitamin A deficiency exists when the chronic failure to eat sufficient amounts of vitamin A or beta-carotene results in levels of blood-serum vitamin A that are below a defined range. Beta-carotene is a form of pre-vitamin A, which is readily converted to vitamin A in the body. Night blindness is the first symptom of vitamin A deficiency. Prolonged and severe vitamin A deficiency can produce total and irreversible blindness. Vitamin A (called retinol in mammals) is a fat-soluble vitamin. The recommended dietary allowance (RDA) for vitamin A is 1.0 mg/day for the adult man and 0.8 mg/day for the adult woman. Since beta-carotene is converted to vitamin A in the body, the body's requirement for vitamin A can be supplied entirely by beta-carotene. Six mg of beta-carotene are considered to be the equivalent of 1 mg of vitamin A. The best sources of vitamin A are eggs, milk, butter, liver, and fish, such as herring, sardines, and tuna. Beef is a poor source of vitamin A. Plants do not contain vitamin A, but they do contain beta-carotene and other carotenoids. The best sources of beta-carotene are dark-green, orange, and yellow vegetables; spinach, carrots, oranges, and sweet potatoes are excellent examples. Cereals are poor sources of beta-carotene. Vitamin A is used for two functions in the body. Used in the eye, it is a component of the eye's light-sensitive parts, containing rods and cones, that allow for night-vision or for seeing in dim-light circumstances. Vitamin A (retinol) occurs in the rods. Another form of Vitamin A, retinoic acid, is used in the body for regulating the development of various tissues, such as the cells of the skin, and the lining of the lungs and intestines. Vitamin A is important during embryological development, since, without vitamin A, the fertilized egg cannot develop into a fetus. Vitamin A deficiency occurs with the chronic consumption of diets that are deficient in both vitamin A and beta-carotene. When vitamin A deficiency exists in the developed world, it tends to happen in alcoholics or in people with diseases that affect the intestine's ability to absorb fat. Examples of such diseases are celiac disease (chronic nutritional disorder), cystic fibrosis, and cholestasis (bile-flow failure or interference). Vitamin A deficiency occurred in infants during the early 1900s in Denmark. The deficiency resulted when milk fat was made into butter for export, leaving the by-product (skimmed milk) for infant feeding. Vitamin A deficiency has taken place in infants in impoverished populations in India, where the only foods fed to the infants were low in beta-carotene. Vitamin A deficiency is also common in areas like Southeast Asia, where polished rice, which lacks the vitamin, is a major part of the diet. The earliest symptom of vitamin A deficiency is night blindness. Prolonged deficiency results in drying of the conjunctiva (the mucous membrane that lines the inner surface of the eyelids and extends over the forepart of the eyeball). With continued vitamin A deficiency, the drying extends to the cornea (xerophthalamia). The cornea eventually shrivels up and becomes ulcerated (keratinomalacia). Superficial, foamy gray triangular spots may appear in the white of the eye (Bitot's spots). Finally, inflammation and infection occur in the interior of the eye, resulting in total and irreversible blindness. Vitamin A status is measured by tests for retinol. Blood-serum retinol concentrations of 30-60 mg/dl are considered in the normal range. Levels that fall below this range indicate vitamin A deficiency. Night blindness is measured by a technique called electroretinography. Xerophthalamia, keratinomalacia, and Bitot's spots are diagnosed visually by trained medical personnel. Vitamin A deficiency can be prevented or treated by taking vitamin supplements or by getting injections of the vitamin. The specific doses given are oral retinyl palmitate (110 mg), retinyl acetate (66 mg), or injected retinyl palmitate (55 mg) administered on each of two successive days, and once a few weeks later if symptoms are not relieved. The prognosis for correcting night blindness is excellent. Xerophthalamia can be corrected with vitamin A therapy. Ulcerations, tissue death, and total blindness, caused by severe vitamin A deficiency, cannot be treated with vitamin A. Vitamin A deficiency can be prevented by including foods rich in vitamin A or beta-carotene as a regular component of the diet; liver, meat, eggs, milk, and dairy products are examples. Foods rich in beta-carotene include red peppers, carrots, pumpkins, as well as those just mentioned. Margarine is rich in beta-carotene, because this chemical is used as a coloring agent in margarine production. In Africa, Indonesia, and the Philippines, vitamin A deficiency is prevented by public health programs that supply children with injections of the vitamin. Key Terms Bitot's spots Bitot's spots are superficial, foamy gray, triangular spots on the white of the eyeball. Carotenoids Carotenoids are yellow to deep-red pigments. Conjunctiva The conjunctiva is a clear layer of cells that covers the eye and directly contacts the atmosphere. The conjunctiva is about five-cells thick. Cornea The cornea is a clear layer of cells that covers the eye, just under the conjunctiva. The cornea is about 50-cells thick. Fat-soluble vitamin Fat-soluble vitamins can be dissolved in oil or in melted fat. Water-soluble vitamins can be dissolved in water or juice. Keratinomalacia Keratinomalacia is ulceration of the cornea. Recommended Dietary Allowance (RDA) The Recommended Dietary Allowances are quantities of nutrients in the diet that are required to maintain good health in people. RDAs are established by the Food and Nutrition Board of the National Academy of Sciences, and may be revised every few years. A separate RDA value exists for each nutrient. The RDA values refer to the amount of nutrient expected to maintain good health in people. The actual amounts of each nutrient required to maintain good health in specific individuals differ from person to person. Xerophthalmia Xerophthalmia is a dry, thickened, lusterless condition of the eyeball resulting from vitamin A deficiency. For Your Information Books Brody, T. Nutritional Biochemistry. San Diego: Academic Press, Inc., 1998. Combs, G. The Vitamins. San Diego: Academic Press, Inc., 1992. Food and Nutrition Board. Recommended Dietary Allowances. 10th ed. Washington, DC: National Academy Press, 1989. Periodicals Filteau, S. M., and A. M. Tomkins."Vitamin A Supplementation in Developing Countries." Archives of Disease in Childhood 72 (1995): 106-109. ______________________

2016-04-09 00:00:37 · answer #5 · answered by Anonymous · 0 0

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