Vit. A deficiency is characterized by all except
Deficiency of Vitamin A The signs of vitamin A deficiency are predominantly ocular. They include nightblindness, conjunctiva) xerosis, Bitot's spots, corneal xerosis and keratomalacia. The term "xerophthalmia" (dry eye) comprises all the ocular manifestations of vitamin A deficiency ranging from nightblindness to keratomalacia, Given below is a sho description of the ocular manifestations. (a) Nightblindness Lack of vitamin A, first causes nightblindness or inability to see in dim light. The mother herself can detect this condition when her child cannot see in late evenings or find her in a darkened room. Nightblindness is due to impairment in dark adaptation. Unless vitamin A intake is increased, the condition may get worse, especially when children also suffer from diarrhoea and other infections. (b) Conjunctiva xerosis This is the first clinical sign of vitamin A deficiency. Theconjuctiva becomes dry and non-wettable. Instead of looking smooth and shiny, it appears muddy and wrinkled. It has been well described as "emerging like sand banks at receding tide" when the child ceases to cry. (c) Bitot's spots Bitot's spots are triangular, pearly-white or yellowish, foamy spots on the bulbar conjunctiva on either side of the cornea. They are frequently bilateral. Bitot's spots in young children usually indicate vitamin A deficiency. In older individuals, these spots are often inactive sequelae of earlier disease. (d)Corneal xerosis This stage is paicularly serious. The cornea appears dull, dry and non-wettable and eventually opaque. It does not have a moist appearance. In more severe deficiency there may be corneal ulceration. The ulcer may heal leaving a corneal scar which can affect vision. (e) Keratomalacia Keratomalacia or liquefaction of the cornea is a grave medical emergency. The cornea (a pa or the whole) may become soft and may burst open. The process is a rapid one. If the eye collapses, vision is lost. EXTRA-OCULAR MANIFESTATIONS These comprise follicular hyperkeratosis, anorexia and growth retardation which have long been recognized. They are non-specific and difficult to quantify. Recent studies seem to indicate that even mild vitamin A deficiency causes an increase in morbidity and moality due to respiratory and intestinal infection . Deficiency of vitamin A has recently been linked to child moality Ref: Park 25th edition Pgno : 654
Bitot's spot
Xerophthalmia
Night blindness
Tranta's spot
Nutrition and health