Xerophthalmia is a public health problem if prevalence of bitot spots is: (A) > 1%, (B) >0.5%, (C) > 0.01%, (D) > 0.05%
Answer is B. Night blindness : > 1%.
Bitot spots : >0.5%.
Corneal ulcer : >0.05%.
Corneal xerosis : >0.01%.