Clinical outcomes and prognostic factors associated with acanthamoeba keratitis.

Cornea Service, Wills Eye Institute, Jefferson Medical College, Thomas Jefferson University, Philadelphia, PA, USA.
Cornea (Impact Factor: 1.75). 10/2010; 30(4):435-41. DOI: 10.1097/ICO.0b013e3181ec905f
Source: PubMed

ABSTRACT To describe the clinical characteristics, time of presentation, risk factors, treatment, outcomes, and prognostic factors on a recent series of Acanthamoeba keratitis (AK) treated at our institution.
Retrospective case series of 59 patients diagnosed with AK from January 1, 2004 to December 31, 2008. Of these 59 patients, 51 had complete follow-up data and were analyzed using univariate and multivariate logistic regression analyses performed with "failure" defined as requiring a penetrating keratoplasty (PKP) and/or having (1) best-corrected visual acuity (BCVA) < 20/100 or (2) BCVA < 20/25 at the last follow-up. A single multivariate model incorporating age, sex, steroid use before diagnosis, time to diagnosis, initial visual acuity (VA), stromal involvement, and diagnostic method was performed.
Symptom onset was greatest in the summer and lowest in the winter. With failure defined as requiring PKP and/or final BCVA < 20/100, univariate analysis suggests that age > 50 years, female sex, initial VA < 20/50, stromal involvement, and patients with a confirmed tissue diagnosis had a significant risk for failure; however, none of these variables were significant using multivariate analysis. Univariate analysis, with failure defined as requiring PKP and/or final BCVA < 20/25, showed stromal involvement and initial VA < 20/50 were significant for failure-only initial VA < 20/50 was significant using multivariate analysis.
Symptom onset for AK is greatest in the summer. Patients with confirmed tissue diagnosis and female patients may have a higher risk for failure, but a larger prospective population-based study is required to confirm this. Failure is likely associated with patients who present with stromal involvement and patients presenting with an initial BCVA worse than 20/50.

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    ABSTRACT: To identify prognostic factors associated with poor outcomes in Acanthamoeba keratitis (AK). Patients with AK treated at the Beijing Tongren Hospital between January 2008 and January 2012 were included. All patients had corneal scrapings and/or cultures positive for Acanthamoeba and visible cysts on in vivo confocal microscopy (IVCM) examination. Therapeutic penetrating keratoplasty was performed in patients who experienced disease progression or lack of improvement on topical therapy. Patient demographics, clinical characteristics, previous treatment, and IVCM characteristics of the cysts were evaluated. Patients defined as poor outcomes were those requiring therapeutic penetrating keratoplasty. Logistic regression was used to estimate the odd-ratio identifying prognostic factors associated with a poor outcome. Twenty-nine eyes of 29 patients were diagnosed as having AK over the study period. IVCM showed clusters and/or chains of Acanthamoeba cysts in 9 patients. Fifteen patients underwent therapeutic penetrating keratoplasty. A late-disease stage on presentation, a deep location of cysts, and clusters or chains of cysts observed with IVCM were significantly associated with a worse outcome. On multivariate analysis, only clusters or chains of cysts observed with IVCM were independently associated with a poor prognosis. The presence of clusters or chains of Acanthamoeba cysts could be a new IVCM criterion allowing the identification of AK patients requiring therapeutic penetrating keratoplasty.
    Journal francais d'ophtalmologie 01/2014; · 0.51 Impact Factor
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    ABSTRACT: Objective To examine the impact of topical corticosteroid use before the diagnosis of Acanthamoeba keratitis (AK) on final visual outcomes and to determine the prognostic factors predicting poorer outcomes. Design Cohort study. Participants A total of 209 eyes of 196 patients with retrievable medical records, diagnosed with AK at Moorfields Eye Hospital, London, between January 1991 and April 2012. One eye was randomly excluded from analysis in the 13 cases of bilateral AK. Methods Patient demographic, initial clinical examination findings, and management details were collected. The outcomes of patients treated with topical corticosteroids before diagnosis of AK were compared with those not treated with topical corticosteroids before diagnosis. A multivariable logistic model, optimized for prior corticosteroid use, was used to derive the odds ratios (ORs) of a suboptimal visual outcome. Main Outcome Measures Suboptimal visual outcome was defined as final visual acuity (VA) ≤20/80, corneal perforation, or need for keratoplasty. Results Acanthamoeba keratitis was diagnosed on microbiological culture in 94 eyes (48.0%), on histopathologic examination in 27 eyes (13.8%), on confocal microscopy in 38 eyes (19.4%), and on the basis of a typical clinical course and response to treatment in 37 eyes (18.9%). Final VA and prior corticosteroid use data were available for 174 eyes (88.8%). In multivariable analysis, corticosteroid use before diagnosis was associated with suboptimal visual outcome (OR, 3.90; 95% confidence interval [CI], 1.78–8.55), as were disease stage 3 at presentation (OR, 5.62; 95% CI, 1.59–19.80) and older age (60+ years) at diagnosis (OR, 8.97; 95% CI, 2.13–37.79). Conclusions Corticosteroid use before diagnosis of AK is highly predictive of a poorer visual outcome. This is largely due to the initial misdiagnosis of AK as herpetic keratitis. It is important to include AK in the differential diagnosis of keratitis in all contact lens users with keratitis, particularly before making a diagnosis of herpes keratitis and before the use of topical corticosteroids in the therapy of any indolent keratitis.
    Ophthalmology 01/2014; · 5.56 Impact Factor
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    ABSTRACT: To report a case of Acanthamoeba keratitis diagnosed using confocal microscopy in a patient corrected by orthokeratology and treated with corneal crosslinking (CXL) after failure to respond to medical treatment. After diagnosis, the patient was treated with several medications until CXL was applied during one 30-min session using ultraviolet A radiation and application of riboflavin. The clinical signs of the disease observed using slit-lamp biomicroscopy and confocal microscopy were evaluated and the visual acuity was measured during the course of the infection and treatment over a period of 30 months including 12 months of medical treatment, 9 months after cross-linking and amniotic membrane transplant and 9 months after penetrating keratoplasty and cataract extraction. In this case, confocal microscopy facilitated early diagnosis of an Acanthamoeba infection even if other signs and symptoms might be confounding. CXL was more effective than aggressive medication against the microorganism. After CXL, the symptoms and the corneal appearance improved significantly but the ulcer did not heal completely. After amniotic membrane transplantation, the patient underwent penetrating keratoplasty (PK) with no rejection, and the visual function substantially improved over 9 months of follow-up. Swimming in contaminated water might represent a risk for orthokeratology patients. CXL was effective for treating Acanthamoeba keratitis in an orthokeratology patient to eliminate active and cystic forms of the microorganism. Confocal microscopy was useful to confirm the diagnosis in the presence of confounding clinical signs observed during a conventional slit-lamp examination. Both CXL and confocal microscopy are essential to the outcome of PK.
    Contact lens & anterior eye: the journal of the British Contact Lens Association 12/2013;

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