1st symptom of vitamin A deficiency: March 2009: (A) Conjunctival xerosis, (B) Bitot's spots, (C) Night blindness, (D) Corneal ulcer
Answer is C. Ans. C: Night blindness Vitamin A deficiency is common in developing countries but rarely seen in developed countries. Night blindness is one of the first signs of vitamin A deficiency. Xerophthalmia and complete blindness can also occur since Vitamin A has a major role in phototransduction. Vitamin A deficiency also diminishes the ability to fight infections. In countries where children are not immunized, infectious disease like measles, have higher fatality rates. Even mild, subclinical deficiency can also be a problem, as it may increase children's risk of developing respiratory and diarrheal infections, decrease growth rate, slow bone development and decrease likelihood of survival from serious illness.