<prompt> The first sign of Vit A deficiency is :Conjunctiva xerosisCorneal ulcerKeratomalaciaBitots spot  <response>: Modified classification WHO Xerophthalmia XN : Night blindnessXIA : Conjunctival xerosis XIB : Bitots spotsX2: Corneal xerosisX3A : Corneal ulcerationkeratomalacia less than 13rd corneal surfaceX3B : Corneal ulcerationkeratomalacia equal to or more than 13rd corneal surface XS : Corneal scarXF : Xerophthalmia fundus. 