<prompt> Xerophthalmia is considered a problem in a community if:-Night blindness 1Bitot spots 1Corneal ulceration 0.05Corneal ulcer 0.5  <response>: Prevalence criteria for determining the Xerophthalmia problem in a community: Criteria Prevalence Night blindness 1.0 Bitots spots 0.5 Corneal xerosis corneal ulceration keratomalacia 0.01 Corneal ulcer 0.05 Serum retinol 5.0 