Impression cytology of the ocular surface: a review

To historically review the technique of impression cytology as a minimally invasive diagnostic tool for ocular surface pathology.

A comprehensive review of published literature cited in PubMed since the first description of impression cytology in 1977 up to date has been undertaken.

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.

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.