Polycarbonate membrane impression cytology: evidence for fluorescein staining in normal and dry eye corneas.

Background/aims: Corneal impression cytology is usually performed with mixed cellulose ester membranes and a limited array of stains. A method using polycarbonate membrane air-dried preparations led to the discovery of fluorescein staining in cells from patients with and without dry eye disease and a membrane-induced defect that was not due to cell removal.

Methods: Impressions after fluorescein installation were performed using polycarbonate and mixed cellulose ester membranes with rapid staining protocols for Diff-Quick as well as haematoxylin and eosin stains.