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Retrospective Study of Acanthamoebic Keratitis During the Past 10 Years

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT02763605
Recruitment Status : Unknown
Verified May 2016 by National Taiwan University Hospital.
Recruitment status was:  Recruiting
First Posted : May 5, 2016
Last Update Posted : May 9, 2016
Information provided by (Responsible Party):
National Taiwan University Hospital

Brief Summary:
Acanthamoebic keratitis is an important corneal disease which may cause severe complication. The difficulty in diagnosis, the difficulty in treatment, and the long treatment process are factors leading to the poor prognosis of these patients. In this retrospective study, the investigators try to analyze the tissue proven Acanthamoebic keratitis diagnosed in our hospital. The investigators will focus on the in vivo confocal microscopic results, the medical history and the medical/surgical treatment outcome. The investigators will collect the tissue proven cases according to the data provided by laboratory diagnosis department and pathological department. The in vivo confocal microscopic results will be collected and analyzed. The investigators will also look through the photography of the external eyes from data stored in PAC system. The medical history and treatment outcome will be studied from clinical chart review. From this study, the investigators aimed to find out a easy way of diagnosing Acanthamoebic keratitis from in vivo confocal microscopy, and find out a better way for treatment.

Condition or disease Intervention/treatment
Acanthamoeba Keratitis Other: no intervention

Detailed Description:

Acanthamoeba keratitis (AK), caused by a pathogenic amoeba, is a sight-threatening corneal infection with severe pain, epithelial defect, epithelial haze, pseudodendrites, and, most characteristically, radial keratoneuritis. The corneal infection of AK was first recognized in the mid 1970s. Since then, a growing number of AK cases were diagnosed, mainly resulting from improper use of soft contact lenses.

Clinical diagnosis of AL is difficult, especially in the early phases of the disease, and it often is misdiagnosed and treated as a herpes simplex infection. It was reported a diagnostic delay of more than 18 days between onset of symptoms and start of anti- amoebic treatment results in a poor disease progress. While definitive diagnosis is made by confirmation of Acanthamoeba cysts or trophozoites in corneal lesions by staining, corneal biopsy, or tissue culturing.

In vivo confocal microscopy was considered useful in the rapid diagnosis of AK. The Acanthamoeba cysts were observed almost exclusively in the epithelial cell layer as highly reflective, round or stellate, high-contrast particles with a diameter of 10 to 20 μm. It was suggested that invasion of Acanthamoeba cysts into Bowman's layer may be a useful predictor for a persistent clinical course. The trophozoites are pear-shaped or irregularly wedge-shaped structures, some surrounded by a brilliant halo some exhibiting fine pseudopodia-like extensions, with mean size of 30.2 µm (range 19.2-55.6μm). It was reported to present in cornea stroma. Highly reflective activated keratocytes forming a honeycomb pattern change was reported to be present around the keratoneuritis. In addition, infiltration of inflammatory cells, possibly polymorphonuclear cells, was observed along with the keratocytes in cases of AK. However, the in vivo confocal microscopic findings in patients with AK is still limited. Some clinical findings may not be correlated with the reports published before.

John K.G. et al recommended clinical treatment toward Acanthamoeba keratitis using Diamidine and Biguanide which are the only two proofed Acanthamoeba cysticidal medication, while Metronidazole is effective in vivo but not in vitro. Topical steroid was considered rather controversial but important and beneficial. It was recommended to use a minimum of 2 weeks of Biguanide prior to the use of topical steroid for inflammation control. When Acanthamoeba keratitis was diagnosed early in the disease course, topical steroid can be spared for the immediate using Diamidine and Biguanide to kill pathogen. In a United Kingdom multicenter study of 218 patients, the average duration of medical therapy was 6 months (range, 0.5 to 29 months). In 2011, a little over half of respondents using corticosteroids in the treatment of Acanthamoeba keratitis. Surgical managements including epithelial debridement, cryotherapy and corneal graft surgery may itself be therapeutic if performed early and promote penetration. Therefore, when Acanthamoeba keratitis was suspected, a long-term and immediate medical treatment may be needed ,and the use of topical steroid toward Acanthamoeba keratitis is still worth investigating.

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Study Type : Observational
Estimated Enrollment : 100 participants
Observational Model: Cohort
Time Perspective: Retrospective
Official Title: Retrospective Study of the in Vivo Confocal Microscopic Findings and the Treatment Outcome of Acanthamoebic Keratitis
Study Start Date : January 2014
Estimated Primary Completion Date : June 2016
Estimated Study Completion Date : July 2016

Group/Cohort Intervention/treatment
patients diagnosed with acanthamoeba keratitis

Inclusion Criteria:

- All patients presenting to National Taiwan University Department from Jun. 1st, 2003 to dec. 30th , 2016 with the tissue proven corneal AK will be included.

Exclusion Criteria

- Patients with tissue proven corneal AK during from Jun. 1st, 2003 to dec. 30th , 2016, but without in vivo confocal data, or complete chart records.

Other: no intervention

Primary Outcome Measures :
  1. Number of participants with typical image finding under an in vivo confocal microscope (Confoscan 3.4.1; Nidek Technologies, Padova, Italy) [ Time Frame: through study completion, an average of about 10 year microscope diagnosis and disease progress prediction of patients with Acanthamoe ]

Information from the National Library of Medicine

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Ages Eligible for Study:   10 Years to 90 Years   (Child, Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No
Sampling Method:   Non-Probability Sample
Study Population
The in vivo confocal microscopic data and medical records of all recruited patients diagnosed with Acanthamoeba Keratitis will be reviewed after approved by the NTUH Institutional Review Board Committee. Data collected include patient demographics (age, gender), local findings, external eye photos, treatment course and treatment outcome. In vivo confocal microscope exam results will be compared with the clinical manifestation.

Inclusion Criteria:

  • presenting to National Taiwan University Department from Jun. 1st, 2003 to dec. 30th , 2016
  • suspecting Acanthamoeba Keratitis by the ophthalmologist
  • drug treatment as Acanthamoeba Keratitis successed
  • tissue proved to be Acanthamoeba Keratitis
  • referred from the other hospital with the diagnose of Acanthamoeba Keratitis

Exclusion Criteria

  • patients suspect corneal Acanthamoeba Keratitis from Jun. 1st, 2003 to dec. 30th , 2013, but without in vivo confocal data, or complete chart records.

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT02763605

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Contact: Chia-ju Lu, MD +886223123456 ext 65197

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National Taiwan University Hospital Recruiting
Taipei, Taiwan, 100
Sponsors and Collaborators
National Taiwan University Hospital
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Study Director: Wei-Li Chen, MD,PHD professor of National Taiwan University


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Responsible Party: National Taiwan University Hospital Identifier: NCT02763605     History of Changes
Other Study ID Numbers: 201312046RINB
First Posted: May 5, 2016    Key Record Dates
Last Update Posted: May 9, 2016
Last Verified: May 2016

Keywords provided by National Taiwan University Hospital:
Acanthamoeba Keratitis
in vivo confocal microscopic

Additional relevant MeSH terms:
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Acanthamoeba Keratitis
Corneal Diseases
Eye Diseases
Eye Infections, Parasitic
Parasitic Diseases
Protozoan Infections
Eye Infections