Impression cytology study of epithelial phenotype of ocular surface reconstructed by preserved human amniotic membrane

OBJECTIVE: To determine the epithelial phenotype of the ocular surface reconstructed by preserved human amniotic membrane. METHODS: Impression cytology was performed in 6 patients who received a large patch of amniotic membrane for conjunctival surface reconstruction during removal of acquired melanosis, conjunctival intraepithelial neoplasia, or bilateral inferior conjunctival chalasis, or for corneal surface reconstruction during removal of pannus associated with limbal deficiency caused by aniridia, toxic epidermal necrolysis, or chemical burn. RESULTS: The nongoblet epithelial cells covering the amniotic membrane were uniformly smaller and the cell density was almost twice that of age- and sex-matched normal control eyes at the corresponding site, and the goblet cell density was almost 10 times that of the control (both P < .05; Student paired t test) (N = 7 eyes). Furthermore, the conjunctival epithelial phenotype with goblet cells was found on corneal surfaces of all 3 patients with limbal deficiency. CONCLUSIONS: The success of conjunctival surface reconstruction correlated well with recovery of the conjunctival epithelial phenotype. The lack of corneal epithelial phenotype even on an avascular corneal stroma supports the concept that conjunctival transdifferentiation does not occur in vivo, and indicates that additional limbal stem cell transplantation is needed for effective corneal surface reconstruction in patients with limbal deficiency.