Various confocal scan features of cysts and trophozoites in cases with acanthamoeba keratitis
PURPOSE. To describe the various con focal scan features of cysts and trophozoites in patients with Acanthamoeba keratitis and to specify the associated findings. METHODS. In a retrospective study of cases between June 2005 and June 2010, we reviewed all the recorded con focal scan images of patients given a high index in regards to clinical suspicion of Acanthamoeba keratitis, in order to specify the various morphometric and morphologic features of Acanthamoeba cysts and trophozoites and to characterize the associated findings in such cases. RESULTS. Confocal scan images of 170 eyes from 170 patients were reviewed. Bilayered, target-shaped, coffee-bean and rod-shaped appearances of the cysts were observed in 100%, 82.9%, 36.4%, and 17.5% of cases, respectively. Single file arrangement of the cysts was noticed in 22 cases. The mean size of the cysts was 18.9 mu m (range 10-39.6). In all cases, trophozoites were observed as pear-shaped or irregularly wedge-shaped structures, some surrounded by a brilliant halo and some exhibiting fine pseudopodia-like extensions, with mean size of 30.2 mu m (range 19.2-55.6). Keratoneuritis and the anterior stromal honeycomb pattern were seen in 28:2% and 5.9% of cases, respectively. CONCLUSIONS. To our knowledge, this is the largest case-series study on con focal scan features of Acanthamoeba cysts and trophozoites in cases with clinical diagnosis of Acanthamoeba keratitis specifying the morphologic and morphometric criteria of this infectious organism and the associated findings.