Xerophthalmia incidence

Impotence Night blindness Retardation of growth Xerophthalmia Increased visuel threshold Dryness of cornea Yes FAT-SOLUBLE p-Carotene not acutely toxic, but supplementation is hot recommended Excess vitamin A can increase incidence of fractures... 

Vitamin A (retinol, retinal, retinoic acid—the three active forms of vitamin A, and p-carotene) function in the maintenance of reproduction, vision, promotion of growth, differen tiation and maintenance of epithelial tissues, and gene expression. A deficiency of vitamin A results in impotence, night blindness, retardation of growth, and xerophthalmia. Large amounts of vitamin A are toxic and can result in an increased incidence of frac tures. 

Katz J, West KP Jr, Khatry SK, et al. Impact of vitamin A supplementation on prevalence and incidence of xerophthalmia in Nepal. Invest Ophthalmol Vis Sci 1995 36 2577-2583. 

Vitamin A supplementation programs have been used in Indonesia, the Phi lip-pi lies, and Africa, where they have resulted in moderate reductions in child mortality and dramatic decreases in the incidence of nightblindness and xerophthalmia. Public health workers have used the following schedule for preventing xerophthalmia and increasing the liver s resen es of vitamin A. Oral retinyl pa Imitate (110 mg), ret In y I acetate (6f> mg), or injected retinyl palmitate (. 5 mg) are administered on each of two successive days, and once a few weeks later if symptoms are not relieved, One approach that seems to be especially workable is to give high-dose capsules at the hme of a scheduled immunization. One clei- er... 

The best documented data on the prevalence and incidence of xerophthalmia in east Asia comes from Indonesia. A major nationwide cross-sectional ocular survey of 36,000 preschool-aged children living in 250 sample sites was conducted in the late 1970s (Sommer, 1982a). In addition, a longitudinal study of approximately 5000 rural preschool children examined every 3-4 months for 2 years was carried out. The risk of developing corneal xerophthalmia before age 5 was 2% and of noncomeal involvement was 52% (WHO, 1982). For the entire... 

In Kenya vitamin A deficiency is common in certain areas but from data now available, does not appear to be a serious public health problem. In northern Nigeria xerophthalmia appears to have a higher incidence than in the tropical rain forest areas of the rest of the country, where provitamin A is more readily... 

There are conflicting reports of a seasonal effect on the appearance of xerophthalmia even within the same country. Hence, in India, Sinha and Bang (1973, 1976) report a seasonal occurrence in the northern West Bengal community they studied, while Chandra et aL (1960) found no seasonality in two areas studied in the southern section of the country. Seasonality where it is observed has been variably attributed to the amount of exposure to ultraviolet sun rays (Oomen and ten Doesschate, 1973), the availability and price of food sources of vitamin A activity (Blankhart, 1967), and the variation in the prevalence of infections, particularly diarrhea (Blankhart, 1967). When more than one of these factors have concurrent peak incidence, the impact on the temporal incidence of xerophthalmia is likely to be cumulative and thus be exhibited seasonally. 

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