In vivo and ex vivo laser confocal microscopy findings in patients with early-stage acanthamoeba keratitis.
OBJECTIVE
This study included in vivo and ex vivo investigations of patients with early-stage Acanthamoeba keratitis by using new-generation laser confocal microscopy (Heidelberg Retina Tomograph 2 Rostock Cornea Module [HRT 2-RCM]).


METHODS
Three patients (2 men and 1 woman; mean age, 22.0 years) with early-stage Acanthamoeba keratitis diagnosed by direct examination (Parker ink-potassium hydroxide stain), culture from corneal epithelial scrapings, or both methods were enrolled in this study. All patients were examined by slit-lamp biomicroscopy. The area of the affected cornea was examined by HRT 2-RCM. Selected images of in vivo corneal layers and ex vivo cultured microorganisms were evaluated qualitatively for shape and degree of light reflection of the corneal structural changes or Acanthamoeba cysts. In addition, cultured Acanthamoeba were examined ex vivo by HRT 2-RCM.


RESULTS
In vivo laser confocal microscopy showed highly reflective round-shaped, high-contrast Acanthamoeba cysts (10-20 microm in diameter) in the corneal epithelium in all cases, leading to rapid confirmation of the clinical diagnosis. In all culture samples of Acanthamoeba, ex vivo laser confocal microscopy showed highly reflective round- or stellate-shaped high-contrast particles (10-20 microm in diameter).


CONCLUSIONS
In vivo laser confocal microscopy enables rapid and noninvasive diagnosis of early-stage Acanthamoeba keratitis with high resolution. In addition, ex vivo laser confocal images of Acanthamoeba cysts may be helpful when similar structures are identified and have to be interpreted under in vivo conditions.
Kobayashi
Akira
A
Department of Ophthalmology, Kanazawa University Graduate School of Medical Science, Kanazawa, Japan. kobaya@kenroku.kanazawa-u.ac.jp
Ishibashi
Yasuhisa
Y
Oikawa
Yosaburo
Y
Yokogawa
Hideaki
H
Sugiyama
Kazuhisa
K
D000048:Acanthamoeba / Q000166:cytology*; D015823:Acanthamoeba Keratitis / Q000175:diagnosis* / Q000188:drug therapy; D000328:Adult; D000818:Animals; D000981:Antiprotozoal Agents / Q000627:therapeutic use; D019573:Epithelium, Corneal / Q000469:parasitology / Q000473:pathology; D005260:Female; D006801:Humans; D008297:Male; D018613:Microscopy, Confocal
D000981:Antiprotozoal Agents