Impression cytology for detection of vitamin A deficiency.

Vitamin A (retinol) deficiency causes blindness, increased morbidity, and mortality among preschool children in many developing nations. Previous studies suggest that impression cytology may represent the first simple, reliable test to detect mild xerophthalmia in young children. We used impression cytology to evaluate and follow up 75 Indonesian preschool children with mild xerophthalmia and an equal number of age-matched, clinically normal neighborhood controls. Results of impression cytology, which were closely correlated with baseline serum vitamin A levels, documented histologic improvement following treatment with vitamin A. Furthermore, results of impression cytology, where abnormal, improved to normal following vitamin A treatment in a significant percentage (23%) of otherwise clinically normal children. Impression cytology appears to detect clinical and physiologically significant preclinical vitamin A deficiency.