Objective: To investigate the cytological feature and differentiate diagnosis of ocular fungal infections by smear cytology.
Methods: Experimental study. One thousand two hundred and twenty-six specimens of smear cytology were collected retrospectively during January 2007- December 2010 from Microbial Laboratory of Beijing Institute of Ophthalmology. The 1226 specimens analyzed in this study were collected from patients who suffered from ocular fungal infections. The corneal scraping cells were observed by Giemsa staining, and the photographic record was saved. The morphological characteristics of fungal pathogens and the surrounding cells were analyzed by light microscopy.
Results: Nine hundred and ninety eight of 1226 (81.40%) specimens were positive with fungal pathogens, 228 of 1226 (18.60%) specimens were fungal negative by smear cytology. 976 of 998 (97.80%) fungal positive specimens were filamentous fungi positive, and 22 of 998 (2.20%) specimens were yeast positive. Among the 998 fungal positive specimens analyzed in this study, twenty-seven (2.71%) were collected from the vitreous, twelve (1.20%) were collected from aqueous humors, thirteen (1.30%) were collected from conjunctiva, seven (0.70%) were collected from eyelid margin, three (0.30%) were collected from lachrymal, and 8 were collected from other parts. The fungal pathogens should be differentiated from the deformed corneal epithelial cells, vacuoles, amebic cyst and other tissue cells during scraping.
Conclusions: The smear cytology test for the diagnosis of ocular fungal infections has advantages of higher detection rate, less time-consuming and easier operation. The identification of fungal like ingredients is very important to improve the accuracy of diagnosis of ocular fungal infections.