<prompt> Vitamin A deficiency is characterized by-Bitot spotXerophthalmiaNight blindnessAll  <response>: Ans. is a i.e., Bitot spot; b i.e., Xerophthalmia c i.e., Night blindnesso The most characteristic and specific signs of vitamin A deficiency are eye lesions.o These develop before the age of 2 years.o The term xerophthalmia comprises all the occular manifestations of vitamin A deficiency.Xerophthalmia Dry eye o It is a syndrome due to deficiency of vitamin A.o It has following stages1. Night blindness Earliest ocular symptom2. Conjuctival xerosis Earliest ocular sign3. Bitots spot4. Corneal xerosisKeratomalacia corneal ulcers 