Overestimation of prevalence of vitamin A deficiency among rural preschool children of West Bengal, India.

Conjunctival xerosis (X1A) as an independent indicator of VAD: VAD is only one of the several causes of conjunctival xerosis; thus the reliability of this sign (X1A) for independent assessment of VAD in field conditions is questionable [3,4]. Conjunctival xerosis is clinically expressed as marked dryness or unwettability; the affected area appears roughened, with fine droplets or bubbles on the surface, rather than smooth and glistening. These changes are best detected in oblique illumination and the abnormalities are often overlooked or, in apparent overcompensation, over-diagnosed. Thus, changes in the conjunctival xerosis by themselves are not an accurate basis for estimating prevalence of clinical xerophthalmia [2,3].