Acanthamoeba keratitis in England and Wales: incidence, outcome, and risk factors

Radford, Cherry

doi:10.1136/bjo.86.5.536

Cited by 312 publications

(265 citation statements)

References 18 publications

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“…It has been previously reported that contact lens use is a major risk factor for AK. 1,2,4,8 Although some reports have suggested that the use of daily-disposable lenses poses only a low risk of AK, 5 seven of the AK patients examined in our study used this type of lens. However, it is difficult to use our results to generalise the level of risk of AK as the usage of daily-type contact lenses differs greatly among countries.…”

Section: Discussionmentioning

confidence: 91%

“…However, polyhexamethyl biguanide (PHMB) and propamidine isethionate are often used in Western countries. 1,4,[6][7][8] Biguanides such as CHG and PHMB are the most effective cysticidal antiamoebics, and are currently used as a firstline treatment for AK. 9 Lim et al 10 compared the therapeutic outcomes for PHMB and CHG treatment and reported that, although the results were non-significant, 78% of eyes receiving PHMB and 86% of eyes receiving CHG were successfully treated.…”

Section: Introductionmentioning

confidence: 99%

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Visual outcome in Japanese patients with Acanthamoeba keratitis

Yamazoe

Yamamoto

Shimazaki-Den

et al. 2012

Eye

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Purpose To identify prognostic factors affecting visual outcome in Acanthamoeba keratitis (AK) treated with topical chlorhexidine gluconate (CHG). Methods A total of 35 eyes in 34 patients with AK were treated with 0.02% topical CHG. Patients were divided into two groups according to the final visual outcome: Group 1, final visual acuity (VA) of 20/25 or greater (22 eyes); Group 2, less than 20/25 (13 eyes). We compared these groups and evaluated the effectiveness of topical CHG compared with outcomes in previous reports. Results Ring infiltrate was observed more often in Group 2 (4.5% vs 61.5%, OR 33.6, 95% confidence interval (CI) 3.4-333.9, Po0.01). The duration between onset and diagnosis of AK was significantly longer (24.9 days vs 48.4 days, OR 1.03, 95% CI 1.00-1.06, P ¼ 0.04) and VA at initial examination (log MAR) significantly lower (0.47 vs 1.59, OR 25.5, 95% CI 3.4-186.7, Po0.01) in Group 2 (visual outcome o20/25). Multivariate analysis revealed that only VA at initial examination was independently associated with worse visual outcome (adjusted OR 24.5, 95% CI 1.9-312.6, P ¼ 0.01). Seventeen (85.0%) of the 20 eyes diagnosed within 1 month and 24 (82.8%) of 29 eyes diagnosed within 2 months achieved a VA of 20/40 or greater. Conclusion VA at initial examination was the most predictive factors for final visual outcome in AK. Topical CHG was comparably effective to other treatments, including polyhexamethyl biguanide and propamidine isethionate.

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Section: Discussionmentioning

confidence: 91%

Section: Introductionmentioning

confidence: 99%

Visual outcome in Japanese patients with Acanthamoeba keratitis

Yamazoe

Yamamoto

Shimazaki-Den

et al. 2012

Eye

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“…There is a lack of recent robust data on the prevalence of Acanthamoeba keratitis in Scotland, but based on a study by Seal et al (1999), the incidence was 149 per million soft contact lens wearers compared with much lower incidence rates of around 18 to 21 per million in the rest of the UK (Radford et al, 2002). Presently, there are approximately 3.7 million contact lens wearers in the UK (British Contact Lens Association, http://www.bcla.org.uk/).…”

Section: Introductionmentioning

confidence: 99%

“…In addition, noncommercial saline solutions have been implicated as potential risk factors (Newton et al, 1986). The UK experienced an increase in cases during the 1990s which coincided with increased use of soft contact lenses (Illingworth et al, 1995).There is a lack of recent robust data on the prevalence of Acanthamoeba keratitis in Scotland, but based on a study by Seal et al (1999), the incidence was 149 per million soft contact lens wearers compared with much lower incidence rates of around 18 to 21 per million in the rest of the UK (Radford et al, 2002). Presently, there are approximately 3.7 million contact lens wearers in the UK (British Contact Lens Association, http://www.bcla.org.uk/).…”

mentioning

confidence: 99%

Acanthamoeba keratitis: improving the Scottish diagnostic service for the rapid molecular detection of Acanthamoeba species

Alexander

Coyne

Jones

et al. 2015

Journal of Medical Microbiology

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Acanthamoeba species are responsible for causing the potentially sight-threatening condition, Acanthamoeba keratitis, which is commonly associated with contact lens use. In this report, we highlight the challenges faced using conventional laboratory identification methods to identify this often under-reported pathogen, and discuss the reasons for introducing the first national service in Scotland for the rapid and sensitive molecular identification of Acanthamoeba species. By comparing culture and molecular testing data from a total of 63 patients (n580 samples) throughout Scotland presenting with ocular eye disease, we describe the improvement in detection rates where an additional four positive cases were identified using a molecular assay versus culture. The testing of a further ten patients by confocal imaging is also presented. This report emphasizes the importance of continuing to improve clinical laboratory services to ensure a prompt, correct diagnosis and better prognosis, in addition to raising awareness of this potentially debilitating opportunistic pathogen. INTRODUCTIONAcanthamoeba keratitis is an uncommon but sightthreatening disease of the cornea caused by free-living protozoan amoebae belonging to the genus Acanthamoeba (Lorenzo- Morales et al., 2013). This painful, often unilateral eye disease may eventually progress to blindness and is associated with contact lens use but can also be diagnosed in non-contact lens wearers. Acanthamoeba species can be found in a variety of different environments including recreational and drinking water, soil and air (Gianinazzi et al., 2009;Legarreta et al., 2013;Rivera et al., 1991). Trophozoites and highly robust cysts can persist for years and are often resistant to drug treatments.Global increases of Acanthamoeba keratitis occurred during the 1970s and 1980s with links to contact lens use in over 85% of cases, which is consistent with recent data from America and Canada (Stehr-Green et al., 1989;Fraser et al., 2012;Page & Mathers, 2013). In addition, noncommercial saline solutions have been implicated as potential risk factors (Newton et al., 1986). The UK experienced an increase in cases during the 1990s which coincided with increased use of soft contact lenses (Illingworth et al., 1995).There is a lack of recent robust data on the prevalence of Acanthamoeba keratitis in Scotland, but based on a study by Seal et al. (1999), the incidence was 149 per million soft contact lens wearers compared with much lower incidence rates of around 18 to 21 per million in the rest of the UK (Radford et al., 2002). Presently, there are approximately 3.7 million contact lens wearers in the UK (British Contact Lens Association, http://www.bcla.org.uk/).An early, accurate diagnosis is crucial for achieving a better prognosis. However, conventional techniques to detect Acanthamoeba species may lack sensitivity, which is likely to result in the true prevalence being underestimated. The challenges of an early diagnosis are compounded by the ability of Acanthamoeba to mimic non-...

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“…Não há métodos padronizados para se testar a sensibilidade de Acanthamoeba sp às várias medicações, nem métodos para se avaliar a erradicação do parasita, uma vez que a recorrência pode ocorrer. Estudos recentes sugerem que a freqüên-cia da infecção por Acanthamoeba seja igual a 1,2 infectados por ano em cada milhão de adultos no país de Gales e na Inglaterra e de 0,2 a 1 indivíduo para cada 10.000 usuários de lentes de contato por ano (12) . A suspeita diagnóstica precoce determina o melhor prognóstico e depende do reconhecimento de sinais clínicos não específicos.…”

Section: Discussionunclassified