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Clinical features and serial changes of Acanthamoeba keratitis: an in vivo confocal microscopy study



To observe the clinical features and serial changes of Acanthamoeba keratitis (AK) during medical treatment by using confocal microscopy.


Thirty-seven patients (37 eyes) diagnosed with AK were included in this study. Confocal microscopy was used to observe the morphology, distribution, and density of Acanthamoeba cysts before and after medication. The differences between cysts and inflammatory cells were identified.


Acanthamoeba cysts were detected at a rate of 94.6% (35/37) by repeated confocal microscopic examinations. The cysts consisting of a lowly light-reflective wall and a high-refractive nucleus, showed cluster or chain distribution in the corneal stroma, which was different from inflammatory cells. After medical therapy, the nucleus of cysts or peripheral corneal tissue gradually dissolved to a hollow configuration. Some of the hollow cysts existed for up to 6 months. The quantity of cysts increased after 1–2 weeks of medication in 23 patients (62.1%), and then began to decrease in 13 patients (35.1 %) who were responsive to anti-amoebic treatment.


Acanthamoeba cysts have many typical clinical features that can be identified by confocal microscopy, which may serve as a valuable tool to guide clinical evaluation and treatment of AK.

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We thank Ping Lin, MTI for her linguistic and editorial assistance.


This study was supported by the National Natural Science Foundation of China (81500702, 81530027), the Shandong Provincial Natural Science Foundation (2016GSF201216), the Taishan Scholar Program Phase II (tspd20150215) and the Innovation Project of Shandong Academy of Medical Sciences.

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Correspondence to Weiyun Shi.

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