<prompt> Xerophthalmia is considered as public health problem if prevalence of bitots spot is more than?0.010.050.501  <response>: Assessment of vitamin A deficiency: The presence of any one of the criteria should be considered as evidence of a xerophthalmia problem in the community. - Criteria Prevalence in population at risk 6 months to 6 years Night blindness more than 1 per cent Bitots spots more than 0.5 per cent Corneal xerosis corneal ulceration keratomalacia more than 0.01 per cent Corneal ulcer more than 0.05 per cent Serum retinol less than 10 mcgdl more than 5 per cent 