Impression cytology of the ocular surface:: a review

Purpose. To historically review the technique of impression cytology as a minimally invasive diagnostic tool for ocular surface pathology. Methods. A comprehensive review Of published literature cited in PubMed since the first description of impression cytology in 1977 up to date has been undertaken. Results. A wide range of processing methods have been adapted to the technique of impression cytology (from conjunctiva, cornea or limbus): regular light microscopy with different stainings, transmission and scanning electron microscopy, immunofluorescence, immunocytochemistry, polymerase chain reaction analysis, immunoblotting analyses, or flow cytometry. At present, it is widely used as a non-invasive alternative to the full-thickness biopsy for the obtention of epithelial cells from the ocular surface. Conclusions. Impression cytology represents a non- or minimally invasive biopsy of the ocular surface epithelium with no side effects or contraindications. It has demonstrated to be a useful diagnostic aid for a wide variety of processes involving the ocular surface. In addition, and mainly during the last decade, its use as a research tool has experienced an enormous growth and has greatly contributed to the understanding of ocular surface pathology. (C) 2003 Elsevier Ltd. All rights reserved.