Abstract:

 Objective   To evaluate the role of laser scanning confocal microscopy (LSCM) in rapid diagnosis and followup examination for Acanthamoeba keratitis. Methods   The clinical manifestation, corneal scraping and culture, and LSCM examination in 4 cases of Acanthamoeba keratitis were retrospectively studied. Results   Corneal opacity, infiltration, stroma mist edema， elastic layer folds, and corneal ulceration were observed in 2 cases by slitlamp microscopy. Typical corneal stromal ring infiltration was observed in 2 cases. Corneal fungal scraping and culture showed negative results in all cases. Amebic cysts were observed under corneal epithelium or within 150μm of shallow stroma by LSCM. Several cysts were observed in 1 case, and 1 cyst was observed in every other case. Cysts assumed round or oval hyperechogenicity with double capsule wall, 25-150μm long, and the core is round. Cysts disappeared and stroma inflammation relieved in 2 cases after treatment. Cysts became smaller, and the structure of double capsule wall was not clear in 2 cases. Trophozoite was observed only in 1 case. Conclusion   The traditional methods to detect Acanthamoeba keratitis, such as corneal scraping and culture, are restricted by corneal material, and positive rate is low. LSCM can be used for rapid noninvasive living inspection of corneal infection, and has advantages of high resolution, accurate depth positioning, dynamic observation, and longitudinal scanning, so it is an important method for rapid etiology diagnosis and followup of Acanthamoeba keratitis.

Key words:  Acanthamoeba keratitis, Diagnosis, Laser scanning confocal microscopy