• Conjunctival impression cytology was performed on 236 Indonesian preschool children, half of whom had mild xerophthalmia and half of whom were age-matched controls. We devised an applicator that applies a paper disk of fixed area to the conjunctiva with even pressure. The disk applicator was used to collect impression cytology specimens from the temporal bulbar conjunctiva of one eye while the original strip technique was used on the other eye. Mean (±SD) serum retinol values for children with normal and abnormal discs were 22.0 ±8.6 μg/dL and 18.0 ±7.2 μg/dL P<.0001). Mean serum values for normal and abnormal strips were 21.7 ±8.6 μg/dL and 19.0 ±7.7 μg/dL (P<.03). Specimens obtained with the new disk applicator corresponded more closely with serum vitamin A levels and therefore vitamin A status than those obtained with the traditional strip technique.
Keenum DG, Semba RD, Wirasasmita S, Natadisastra G, Muhilal , West KP, Sommer A. Assessment of Vitamin A Status by a Disk Applicator for Conjunctival Impression Cytology. Arch Ophthalmol. 1990;108(10):1436-1441. doi:10.1001/archopht.1990.01070120084034