In Vivo and In Vitro Laser Confocal Microscopy to Diagnose Acanthamoeba Keratitis

Purpose: To determine the effectiveness of laser confocal microscopy in identifying Acanthamoeba cysts and trophozoites in the cornea of patients with Acanthamoeba keratitis (AK) and to evaluate its effectiveness in following AK after treatment. Methods: The corneas of 9 patients clinically diagnosed with AK were monitored periodically with the Heidelberg Retina Tomograph II-Rostock Cornea Module (HRT II-RCM) to examine for Acanthamoeba cysts and trophozoites during the clinical course. Results: Seven of 9 patients had positive corneal smears, and 5 of 9 patients had positive laboratory cultures. HRT II-RCM demonstrated the presence of highly reflective polygonal shadows with lower reflective borders in the cornea of all patients. In 1 patient, a highly reflective pleomorphic shadow with small less-reflective areas was detected inside the cell. The former finding resembled the image of Acanthamoeba cysts in culture as observed by HRT II-RCM, and the latter observation with that of Acanthamoeba trophozoites in culture. After treatment, the number of highly reflective inflammatory cells decreased and the number and morphology of the corneal epithelial cells with highly reflective nuclei recovered to normal levels. Conclusion: These results indicate that in vivo laser confocal microscopy can be a useful method to make a diagnosis and to follow patients with AK.

[1]  E. Cohen,et al.  Acanthamoeba Keratitis: A Parasite on the Rise , 2007, Cornea.

[2]  W M Petroll,et al.  Clinical and diagnostic use of in vivo confocal microscopy in patients with corneal disease. , 1993, Ophthalmology.

[3]  W. Mathers,et al.  Diagnosis of Acanthamoeba Keratitis In Vivo with Confocal Microscopy , 1995, Cornea.

[4]  D. Frazer,et al.  A review of 72 consecutive cases of Acanthamoeba keratitis, 1984–1992 , 1993, Eye.

[5]  W Matthew Petroll,et al.  Tandem scanning confocal corneal microscopy in the diagnosis of suspected acanthamoeba keratitis. , 2006, Ophthalmology.

[6]  J. D. Cameron,et al.  Confocal microscopy findings of Acanthamoeba keratitis. , 1996, American journal of ophthalmology.

[7]  R Folberg,et al.  Confirmation of confocal microscopy diagnosis of Acanthamoeba keratitis using polymerase chain reaction analysis. , 2000, Archives of ophthalmology.

[8]  Y. Shimomura,et al.  Utility of Fungiflora Y stain in rapid diagnosis of Acanthamoeba keratitis , 1999, The British journal of ophthalmology.

[9]  J. Niederkorn,et al.  The pathophysiology of Acanthamoeba keratitis. , 2006, Trends in parasitology.

[10]  K. Sugiyama,et al.  In Vivo and Ex Vivo Laser Confocal Microscopy Findings in Patients With Early-stage Acanthamoeba Keratitis , 2008, Cornea.

[11]  N. Khan.  Pathogenesis of Acanthamoeba infections. , 2003, Microbial pathogenesis.

[12]  C J Koester,et al.  In vivo scanning slit confocal microscopy of Acanthamoeba keratitis. A case report. , 1994, Cornea.

[13]  E. Cohen,et al.  Confocal microscopy: a report by the American Academy of Ophthalmology. , 2004, Ophthalmology.