Background-For epidemiological and therapeutic reasons early diagnosis of superficial viral infections is crucial. Conventional microbiological techniques are expensive, time consuming, and not suYciently sensitive. In this study impression cytology techniques were evaluated to analyse their diagnostic potential in viral infections of the ocular surface. Method-A Biopore membrane device instead of the original impression cytology technique was used to allow better quality and handling of the specimens. The impressions were processed, using monoclonal antibodies and immunoperoxidase or immunofluorescence techniques to assess the presence of herpes simplex virus, varicella zoster virus, or adenovirus antigens. Ocular surface specimens from healthy individuals (n=10) and from patients with suspected viral surface disease (n=19) were studied. Infected and non-infected cell cultures served as controls. (Br J Ophthalmol 1997;81:984-988) Early identification of the causative organism is highly desirable for the management of infectious eye diseases. Because of the epidemiological and therapeutic consequences rapid microbial diagnosis would be particularly helpful in herpetic or adenoviral disease of the ocular surface. In these conditions the initial diagnosis still relies mainly on clinical signs, although progress has been made in the development of diagnostic techniques. [1][2][3] Culturing is still regarded as the standard for the diagnosis of viral diseases. 4 Results by this method, however, are available only after several days and depend on viable, infectious material that usually has to be transferred to a specialised laboratory for processing. 5 Rapid diagnostic tests that allow processing on site and give results within hours, hence avoiding these problems, were developed and evaluated in the 1980s. 6-11 These tests, based on immunocytological staining of conjunctival scrapings, produced rapid results with good specificity but only moderate sensitivity. 12 The limited sensitivity was caused probably by the collection technique that bears the risk of losing (or missing) the few infected cells. These tests were therefore never really adopted by ophthalmologists.
Results-ThisEpithelial cells from the conjunctiva and the cornea lose their adhesion to neighbouring cells when they become infected, and this makes them an ideal target for impression cytology. This technique was first reported by Egbert and coworkers in 1977 13 who found that an imprint of the superficial cell layer could be obtained by pressing a cellulose acetate filter on the ocular surface. Modified by several authors, this non-invasive biopsy technique was rapidly adopted and used for histological studies on dry eyes, vitamin deficiencies, ocular cicatricial pemphigoid, but only occasionally for microbiological tests. [14][15][16][17][18][19][20][21][22] Despite the theoretical simplicity and diagnostic potential of this method, its advantages have been outweighed by the inconvenience of the technique in use and therefore impression ...
