In vivo imaging of radial keratoneuritis in patients with Acanthamoeba keratitis by anterior-segment optical coherence tomography.

PURPOSE: To investigate in vivo corneal changes of radial keratoneuritis in early-stage Acanthamoeba keratitis (AK) using anterior-segment optical coherence tomography (AS-OCT). DESIGN: Single-center, prospective clinical study. PARTICIPANTS: Four eyes (4 patients with a mean age of 28.5 years) with early-stage AK showing radial keratoneuritis were included in this study. Definitive diagnosis was made by confirmation of AK cysts using in vivo confocal microscopy and culture. METHODS: Anterior-segment OCT examination was performed on the initial visit and at follow-up visits paying special attention to radial keratoneuritis. MAIN OUTCOME MEASURES: Selected AS-OCT images of the cornea were evaluated qualitatively for the shape and degree of light reflection of abnormal neurons. RESULTS: With the use of AS-OCT, we successfully obtained high-resolution images of putative radial keratoneuritis in all patients as highly reflective bands or lines in the corneal stroma. The depth and width of the highly reflective bands/lines varied from case to case (anterior stroma to mid-stroma, from 20 to 200 µm). Some lines ran obliquely from the deep peripheral stroma toward the anterior stroma, and some were located at different depths (subepithelial and mid-stroma) and ran relatively parallel to the corneal layers. After appropriate treatment, radial keratoneuritis was resolved by both slit-lamp biomicroscopy and AS-OCT in all patients. CONCLUSIONS: High-resolution Fourier-domain AS-OCT provides novel and detailed visual information of radial keratoneuritis in patients with early-stage AK. Visualization of radial keratoneuritis by AS-OCT may be a useful adjunct to the diagnosis and follow-up of early-stage AK.

In vivo laser confocal microscopy findings of radial keratoneuritis in patients with early stage Acanthamoeba keratitis.

OBJECTIVE: To investigate in vivo corneal changes of keratoneuritis in early stage Acanthamoeba keratitis (AK) using in vivo laser confocal microscopy. DESIGN: Single-center, prospective, clinical study. PARTICIPANTS: Thirteen eyes (12 patients; 5 men and 7 women; mean age ± standard deviation, 22.3 ± 4.2 years) with keratoneuritis resulting from early stage AK were included in this study. TESTING: In vivo laser confocal microscopy was performed, paying special attention to keratoneuritis. MAIN OUTCOME MEASURES: Selected confocal images of corneal layers were evaluated qualitatively for shape and degree of light reflection of abnormal cells and deposits. RESULTS: In all patients, Acanthamoeba cysts were observed clearly in the basal epithelial cell layer as highly reflective round particles with a diameter of 10 to 20 µm. Bowman's layer infiltration of Acanthamoeba cysts was observed in only 1 case, and no cases showed stromal or nerve infiltration of Acanthamoeba cysts. In the stroma, all cases showed highly reflective activated keratocytes forming a honeycomb pattern; these changes were significant around the keratoneuritis. Infiltration of inflammatory cells, possibly polymorphonuclear cells, was observed along with keratocyte bodies in all cases. Numerous highly reflective spindle-shaped materials were observed around the keratoneuritis. Most notably, highly reflective patchy lesions were observed around the keratoneuritis in 11 cases (84.6%). Inflammatory cells also were observed in the endothelial cell layer in 4 cases (30.8%). CONCLUSIONS: In vivo laser confocal microscopy identified consistent corneal abnormalities around keratoneuritis in early stage AK patients, of which highly reflective patchy lesions may be characteristic of keratoneuritis. Further morphologic studies of corneas with early stage AK in a larger number of patients may elucidate the clinical significance of radial keratoneuritis and may help us to understand the interaction between Acanthamoeba organisms and host corneal cells or nerves.

[Survey of severe contact lens-associated microbial keratitis in Japan].

PURPOSE: To understand the current state of severe contact lens (CL)-associated microbial keratitis in Japan. METHOD: The survey was conducted by the Japan Contact Lens Society and the Japanese Association for Ocular Infection in 224 facilities from April 2007 to March 2009. Patients who were diagnosed with CL-associated microbial keratitis and hospitalized for treatment were enrolled. Clinical characteristics of the keratitis, microbiologic findings and the status of CL hygiene were studied. RESULTS: A total of 350 patients were investigated, with an average age of 28.0 (9-90) years. Acanthamoeba was identified in 85 (24.3%) corneal specimens and Pseudomonus aeruginosa in 70 (20.0%) cases. One hundred ninety six (56.0%) patients were frequent replacement soft CL users. Extended wearing of daily-use CLs was found in 77 (22.0%) patients. Only 67 cases maintained good CL hygiene by daily rubbing-washing and the poor CL care situation was reviewed. CONCLUSION: The most frequently detected pathogenic microorganism was Acanthamoeba, followed by Pseudomonus aeruginosa. Our survey showed the importance of keeping good CL hygiene by proper lens care, and improvement of CL-related social regulations is urgently needed.

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.

Bowman's layer encystment in cases of persistent Acanthamoeba keratitis.

BACKGROUND: The purpose of this study was to report Acanthamoeba encystment in Bowman's layer in Japanese cases of persistent Acanthamoeba keratitis (AK). METHODS: Laser confocal microscopic images of the cornea were obtained in vivo from 18 consecutive eyes from 17 confirmed AK patients. Retrospectively, 14 cases treated over 4 months were categorized as a nonpersistent group and three cases that required prolonged therapy for more than 6 months were categorized as a persistent group. Clinical outcomes based on final best-corrected visual acuity were retrospectively analyzed, and selected confocal images were evaluated qualitatively for abnormal findings. RESULTS: The final best-corrected visual acuity was significantly lower (P < 0.01) for patients in the persistent group compared with that in the nonpersistent group. At the initial visit, in vivo confocal microscopy demonstrated Acanthamoeba cysts exclusively in the epithelial layer in both the nonpersistent group (80%) and the persistent group (100%). At a subsequent follow-up visit, numerous Acanthamoeba cysts were observed in the epithelial cell layer and in Bowman's layer in all patients with persistent AK, but Acanthamoeba cysts were undetectable in all cases with nonpersistent AK tested. CONCLUSION: Invasion of cysts into Bowman's layer was characteristically observed in patients with persistence of AK. This finding suggests that invasion of Acanthamoeba cysts into Bowman's layer may be a useful predictor for a persistent clinical course.

Ex vivo laser confocal microscopy findings of cultured Acanthamoeba trophozoites.

PURPOSE: The purpose of the current study was to investigate ex vivo laser confocal microscopic findings of cultured Acanthamoeba trophozoites obtained from Acanthamoeba keratitis patients. METHODS: Eight cultured samples of Acanthamoeba trophozoites from eight eyes of seven patients (mean age, 26.9 years; age range, 18-52 years) were used. Seven samples were from corneal scrapings of Acanthamoeba keratitis patients and one sample was from the solution in a soft contact lens case. Ex vivo laser confocal microscopy was performed to qualitatively evaluate the shape and degree of light reflection of the living Acanthamoeba trophozoites. RESULTS: Ex vivo laser confocal microscopy demonstrated highly reflective, high-contrast Acanthamoeba trophozoites with no walls (mean size, 25.4 µm; range, 17.1-58.5 µm). The shapes of the trophozoites were highly pleomorphic, and some showed characteristic acanthopodia by laser confocal microscopy. CONCLUSION: Ex vivo laser confocal microscopy was effective in demonstrating cultured Acanthamoeba trophozoites of various shapes and sizes. The observations of the current study may be helpful when similar structures are identified under in vivo conditions.