Impact of Acanthamoeba Keratitis on the Vision-Related Quality of Life of Contact Lens Wearers.

PURPOSE: The aim of this study was to determine the impact of Acanthamoeba keratitis (AK) caused by contact lens (CL) use on vision-related quality of life (VRQOL) and the sociodemographic factors and disease outcome associated with VRQOL. METHODS: Sixty-one CL-associated AK cases and 59 asymptomatic CL wearers (mean age ±SD 39.4 ± 16.5 vs. 45.5 ± 15.2 yrs, P = 0.04) were recruited from Moorfields Eye Hospital and Institute for Optometry, London. AK cases were surveyed during active disease and were stratified into "poor" and "good" outcomes based on clinical features. VRQOL was measured using Rasch-transformed scores from the Emotional, Mobility, and Reading domains of the 32-item Impact of Visual Impairment questionnaire. AK cases were compared with controls and "poor" outcomes compared with "good" with multivariable linear regression. Multivariable linear regression models were also used to identify the sociodemographic factors and disease outcome associated with VRQOL. RESULTS: AK was associated with significant and substantial reductions in all 3 evaluated domains of VRQOL (Reading -59.6%, Mobility -59.8%, and Emotional -66.2%) compared with controls, independent of sociodemographic factors. Patients with AK who experienced poor outcomes, those who were of British White race (compared with all other races) and female, had lower VRQOL scores across all domains. Patients with AK with lower incomes scored worse on Reading and Mobility domains, whereas those with lower education had poorer Emotional scores. CONCLUSIONS: AK has a considerable detrimental impact on VRQOL. Clinicians should consider the importance of referring patients with AK for rehabilitative support and counseling as part of active disease management.

Acanthamoeba Keratitis: Perspectives for Patients.

Purpose: To unveil the long-term prognosis of Acanthamoeba keratitis based on clinical presentation and timing of diagnosis to better inform patients since the first visit regarding their length of treatment, quality of life, and visual function.Methods: Retrospective observational study enrolling patients with Acanthamoeba keratitis from 1994 to 2019. Patients with a complete eye examination and medical records were analyzed. The severity of the disease, the time from onset of symptoms to the appropriate therapeutic regimen, the time until clinical resolution, visual function, and long term follow-up was evaluated. Quality of life was assessed at the last follow-up visit by means of the VFQ-25 questionnaire.Results: Thirty-five patients (40 eyes) were assessed. The overall healing time of patients with Acanthamoeba keratitis was 12.5 ± 3.5 months, while patients with a severe corneal ulcer (stage III) had a significant longer healing time (16.2 ± 3.7 months) compared to patients with stage II (7.04 ± 0.7 months) or I (7.7 ± 1.5 months; p < .05). Patients who received a prompt therapy (<30 days form symptoms onset) had a reduced healing time compared to patients with a delayed diagnosis (p < .01). Quality of life was assessed after a mean of 11.7 ± 4.7 years and it was mildly reduced (86.6 ± 17). Patients that were diagnosed early (<30 days from onset) showed a lower reduction in quality of life than in patients that were diagnosed >30 days from onset. After resolution, 59% of the patients considered unnecessary any further proposed surgical intervention.Conclusions: Delayed diagnosis of Acanthamoeba keratitis and disease severity significantly increases healing time and duration of treatment. The time to diagnosis and disease stage at diagnosis predicts the duration of treatment, the final outcome, quality of life, and the requirement of surgery. These data would allow us to promptly inform patients about long-term disease timeline, future outcomes, improving disease acceptance, and quality of life.

Acanthamoeba keratitis: a review of biology, pathophysiology and epidemiology.

Acanthamoeba keratitis is an infection caused by a unicellular protozoan of the genus Acanthamoeba that is universally widespread. Until now, most cases were reported in contact lens wearers, although it is also a reality for non-wearers, mostly connected to corneal trauma. There is also a variation in incidence regarding the aetiology of the disease between developed and developing countries. PURPOSE: This work is based on a literature review, and the main goal is to deepen the knowledge about Acanthamoeba keratitis, presenting the main risk factors and focusing on prevention actions for this type of corneal infection since the treatments are not always effective. It targets specialists in visual health to strengthen their knowledge in this area, as well as to allow them to better inform their patients about hygiene care, appropriate measures of disinfection and ways to minimise the risk of infection. At this stage, it is important to highlight the essential role that practitioners play in fitting, monitoring and following-up patients to minimise the danger of infection. RECENT FINDINGS: It is well recognised that corneal trauma facilitates invasion by leaving an open door for microorganisms to penetrate the cornea. In addition to trauma, risk factors are mostly associated with patients' behaviours, such as interaction of contact lenses with contaminated water in the shower, swimming pools and beaches, etc., lack of hygiene habits with contact lenses and respective cases, and the use of ineffective disinfecting solutions. The fact that a disinfecting solution is not completely effective against trophozoites and/or cysts, both forms of Acanthamoeba's lifecycle, can cause the infection since one cyst alone leads to the emergence of a whole new population of Acanthamoeba. SUMMARY: It is necessary to reduce the risk of infection and, beyond the need to promote patient education to encourage correct CL hygiene behaviours, it should also be highlighted that there is an urgent need to enhance the efficacy of CL disinfection systems against all strains and both stages of Acanthamoeba through the creation of standardised methods. The ease of purchasing CLs without any supervision must also be considered a concern, and, in the near future, it is also important to develop and implement effective diagnostic methods and treatments for Acanthamoeba keratitis.

A 5-Year Review of Acanthamoeba Keratitis Related to Wearing Contact Lenses in Korea.

PURPOSE: To investigate the presentation, clinical characteristics, and outcomes of Acanthamoeba keratitis (AK) in Busan, South Korea, over a 5-year period. METHODS: This retrospective study involved a review of the medical records of 16 patients (19 eyes in total) who were diagnosed with AK, related to wearing contact lenses, at the tertiary hospital, Pusan National University Hospital at Busan City, from December 2013 to December 2018. RESULTS: Nineteen eyes of 16 patients with a diagnosis of AK were identified. The average age of the patients was 21.1±12.6 years; there were 2 men and 14 women. The mean period from the onset of the first symptoms to diagnosis was 7.0±6.5 days. The average initial visual acuity was 0.78±0.37 (tested on a logarithm of the minimum angle of resolution chart), and the final visual acuity after treatment was 0.07±0.07, indicating a significant improvement (P=0.001). A variety of corneal lesions were identified. Early diagnosis of AK was associated with a significantly better final visual acuity. CONCLUSION: The average therapeutic period for AK, when a surface epithelial lesion of the cornea was identified, was 4 months compared with an average period of over 6 months for a deeper stromal lesion. Therefore, this study highlights the fundamental importance of early diagnosis, preventing deeper layers of the cornea from being affected, and appropriate management to ensure a favorable outcome.

In Vivo Confocal Microscopy Morphologic Features and Cyst Density in Acanthamoeba Keratitis.

PURPOSE: To correlate in vivo confocal microscopy morphologic features (IVCM-MF) and Acanthamoeba cyst density (ACD) with final best-corrected visual acuity (BCVA) in Acanthamoeba keratitis (AK). DESIGN: Retrospective cohort study. METHODS: Patient demographics, treatment outcome, and corresponding IVCM-MF performed at the acute stage of infection were analyzed. Inclusion criteria were microbiological positive AK cases seen at Moorfields Eye Hospital between February 2013 and October 2017. Statistical significance was assessed by multinomial regression and multiple linear regression analysis. Main outcome measure was final BCVA. RESULTS: A total of 157 eyes (157 patients) had AK. Absence of single-file round/ovoid objects was associated with a BCVA of 6/36 to 6/9 (odds ratio [OR] 8.13; 95% confidence interval [CI], 1.55-42.56, P = .013) and ≥6/6 (OR 10.50; 95% CI, 2.12-51.92, P = .004) when compared to no perception of light to 6/60. Absence of rod/spindle objects was associated with a BCVA of ≥6/6 (OR 4.55; 95% CI, 1.01-20.45, P = .048). Deep stromal/ring infiltrate was associated with single-file round/ovoid objects (OR 7.78; 95% CI, 2.69-22.35, P < .001), rod/spindle objects (OR 7.05; 95% CI, 2.11-23.59, P = .002), and binary round/ovoid objects (OR 3.45; 95% CI, 1.17-10.14, P = .024). There was a positive association between ACD and treatment duration (ß = 0.14, P = .049), number of IVCM-MF (ß = 0.34, P = .021), and clusters of round/ovoid objects (ß = 0.29, P = .002). CONCLUSIONS: Specific IVCM-MF correlate with ACD and clinical staging of disease, and are prognostic indicators for a poorer visual outcome.

Acanthamoeba keratitis therapy: time to cure and visual outcome analysis for different antiamoebic therapies in 227 cases.

AIMS: To test the hypothesis that Acanthamoeba keratitis (AK) outcomes differ for different topical antiamoebic therapies (AAT) and to provide the detailed patient outcome data. METHODS: A retrospective cohort study of 227 patients developing AK between 25 July 1991 and 10 August 2012. Inclusion criteria required a complete record of AAT treatment for both the primary outcome of a medical cure rate at 12 months and the secondary outcome of Snellen visual acuity ≤6/24 and/or surgical intervention. Analysis used multivariable regression to control for differences in baseline disease characteristics for both primary and secondary outcomes with unadjusted analyses for other outcomes. Subjects were categorised for analysis both by the AAT used at baseline and also by mutually exclusive AAT (patients exposed to all the drugs in each group, and no others, for some period). AAT categories were PHMB monotherapy, PHMB+diamidine, PHMB+chlorhexidine+diamidine, diamidine monotherapy and other AAT. RESULTS: Analysis by baseline AAT showed no notable difference between treatments for both a medical cure at 12 months in 60.79% (138/227) or for a poor outcome in 49.34% (112/227). When AATs were analysed by mutually exclusive groups, PHMB monotherapy provided the best outcomes. These findings are subject to bias requiring careful interpretation. Overall cure rates for the 214 subjects with resolved outcomes were 94.27% (214/227), median time to cure 5 months (IQR 3.25-9.00 months) and range 1-26.24 months. CONCLUSION: PHMB 0.02% monotherapy for the initial treatment of AK is as effective as biguanide+diamidine combination therapy. Chlorhexidine monotherapy was too infrequent for comparison. The outcome data are the most detailed available.

The rising incidence of Acanthamoeba keratitis: A 7-year nationwide survey and clinical assessment of risk factors and functional outcomes.

PURPOSE: To evaluate the incidence of Acanthamoeba keratitis in the Netherlands between 2009 and 2015 and to analyse predicting factors for treatment outcome. METHODS: Patient characteristics, diagnostic methods, diagnostic delay, therapy prior to and after diagnosis, and visual outcome were obtained from medical files of all patients diagnosed with Acanthamoeba keratitis in the Netherlands between 2009 and 2015. A logistic regression analysis on treatment failure, defined as a best corrected visual acuity of less than 20/40 Snellen decimals (i.e. >0.3 logMAR or an approximate loss of three lines of visual acuity) and/or the need for keratoplasty, was performed to determine predicting factors. RESULTS: Two hundred and twenty-four eyes of 224 patients were included. Ninety-five percent of the patients were contact lens wearers, of whom 74% wore soft contact lenses. The number of cases increased from 16 in 2009 to 49 in 2015. This resulted in an estimated incidence of 1 in 21,000 for soft contact lens wearers in 2015. Eighty-seven eyes (39%) met the criteria for treatment failure. In a multivariable regression analysis, higher age at presentation, a higher severity stage and corticosteroid use before diagnosis were positively correlated with treatment failure. Early referral to a cornea specialist was associated with better clinical outcomes. CONCLUSIONS: Although Acanthamoeba keratitis is still a relatively uncommon disease, the incidence in soft contact lens wearers has increased to reach 1 in 21,000 in 2015. Treatment failure occurred in 39% of cases, with age, higher severity stage, corticosteroid use before diagnosis and indirect referral to a cornea specialist as important risks factors.

Acanthamoeba Keratitis: Are Recent Cases More Severe?

PURPOSE: To identify a recent change in disease severity and visual outcomes of patients with Acanthamoeba keratitis (AK) at Wills Eye Hospital (WEH). METHODS: A retrospective chart review was performed of all cases diagnosed with AK at WEH between January 1, 2009, and December 31, 2015. Failure of treatment was defined as having a final best-corrected visual acuity worse than 20/100 and/or requiring keratoplasty. The patients were grouped into 2 outcome categories: successfully treated and those who failed treatment; and prognostic factors associated with failure status were evaluated. Additionally, patients who presented from 2009 to 2012 (labeled "first interval") were compared with those who presented more recently from 2013 to 2015 (labeled "second interval") to determine whether the treatment outcomes and patients' characteristics from the 2 intervals were different. RESULTS: Fifty-nine patients were diagnosed. The rate of treatment failure in the second interval was significantly higher than in the first interval (68% vs. 28%, P = 0.004). Compared with the patients in the first interval, those who presented in the second interval were significantly older, were treated with more corticosteroids before diagnosis, had more days from the symptom onset to initiation of AK treatment, and presented to WEH with poorer vision. CONCLUSIONS: In recent years, the general profile of patients with AK has changed at WEH. Currently, we are treating older patients with more severe keratitis who are presenting later and with worse vision compared with our previous patients. At the same time, treatment outcomes have been poorer.

Risk factors, demographics and clinical profile of Acanthamoeba keratitis in Melbourne: an 18-year retrospective study.

PURPOSE: To assess incidence, risk factors, presentation and final visual outcome of patients with Acanthamoebakeratitis (AK) treated at the Royal Victorian Eye and Ear Hospital (RVEEH), Melbourne, Australia, over an 18-year period. METHODS: A retrospective review of all cases of AK managed at RVEEH between January 1998 and May 2016 was performed. Data collected included age, gender, affected eye, signs and symptoms, time between symptoms and diagnosis, risk factors, presenting and final visual acuity (VA), investigations, medical treatment, surgical interventions and length of follow-up. RESULTS: A total of 36 eyes affected by AK in 34 patients were identified. There were 26 cases diagnosed early (<30 days) and 10 were diagnosed late (≥30 days). There were 31 (86.1%) cases associated with contact lens (CL). Signs associated with early AK included epithelial infiltrates, while signs of late AK included uveitis, ring infiltrate, endothelial plaque and corneal thinning (p<0.05). Surgical treatment was required in seven cases (19.4%). There were 29 (80.6%) cases that reported improved VA. Median best corrected final VA was worse in patients with late diagnosis (logarithm of minimal angle of resolution (logMAR) 0.5, IQR: 0.2-0.8), compared with patients with early diagnosis (logMAR 0.0, IQR: 0.0-0.3; p=0.01). Late diagnosis was associated with a prolonged disease period. CONCLUSION: AK was an uncommon cause of severe keratitis and was associated commonly with CL. Patients with late diagnosis had worse presenting and final VAs as well as a prolonged disease period, indicating need for early recognition and management.

First time identification of Acanthamoeba genotypes in the cornea samples of wild birds; Is Acanthamoeba keratitis making the predatory birds a target?

Acanthamoeba is a free-living amoeba which can be isolated from environment and among others well known as an opportunist protozoan parasite causing infections in humans and animals. Eyes are extremely important for the wild birds and losing sight ability due to Acanthamoeba can be dangerous. The studies on Acanthamoeba infection in wild birds is very few in world and Turkey therefore we aimed to screen deceased wild birds found in Izmir and Manisa provinces located in western Turkey using PCR and non-nutrition agar (NNA) plate method. Cornea samples were obtained from 18 deceased wild birds. During the external examination, signs of keratitis were observed in two Eurasian sparrowhawks (Accipiter nisus). All of the corneal samples were analyzed by two PCR methods and NNA plate. According to results, the Acanthamoeba positivity in corneal samples was 16.6% and 5.5% by PCR and plate method, respectively. According to sequencing data, two of isolates belonged to genotype T5 and one was genotype T4. In conclusion, Acanthamoeba infection was detected in wild bird cornea samples with/without keratitis for the first time in the world. The result of this study also show that Acanthamoeba can be a cause of keratitis in wild birds of Turkey and thus these predator birds can be a target of other wild animals due to loss of sight ability. In terms of public health, these results show the importance of wild birds as a source of Acanthamoeba infection in nature.

The Relation of Ocular Surface Irregularity and Visual Disturbance in Early Stage Acanthamoeba Keratitis.

PURPOSE: To evaluate the relation between ocular surface irregularity and visual disturbance in early stage Acanthamoeba keratitis (AK). METHODS: Fifteen patients with culture-proven AK underwent routine ophthalmic examinations, including best-corrected visual acuity (BCVA) measurement, slitlamp biomicroscope examination, and corneal fluorescein dye staining test, in both the eyes. We also evaluated the corneal sensitivity with Cochet-Bonnet esthesiometer, tear functions by Schirmer's test, and ocular surface irregularity by corneal topography and compared the results with the contralateral healthy eyes in this study. RESULTS: The mean logarithm of the minimum angle of resolution BCVA (0.71±0.77) was significantly lower in the eyes with AK (P=0.002). Epithelial disorders were present in all eyes, and radial keratoneuritis in 14 eyes (93.3%). The mean corneal sensitivity (39.3±24.1 mm) was significantly lower in eyes with AK compared with the healthy eyes (P=0.005). The mean Schirmer's test value (22.5±12.0 mm) in eyes with AK was significantly higher compared with the healthy eyes (P=0.01). The ocular surface irregularity indices (the surface regularity index, 2.47±0.42; the surface asymmetry index, 3.24±1.31) were significantly higher in eyes with AK compared with contralateral healthy eyes (P<0.0001 and P<0.0001, respectively). CONCLUSIONS: The ocular surface disease in AK is associated with decrease in corneal sensitivity and increase in Schirmer's test value and ocular surface irregularity indices. The visual disturbance in AK may owe not only to corneal haze but also to ocular surface irregularity.

The Impact of Topical Corticosteroids Used in Conjunction with Antiamoebic Therapy on the Outcome of Acanthamoeba Keratitis.

PURPOSE: To examine the impact of topical corticosteroid use after the start of antiamoebic therapy (AAT) on the outcomes of Acanthamoeba keratitis (AK) therapy. DESIGN: Cohort study. PARTICIPANTS: A total of 196 patients diagnosed with AK at Moorfields Eye Hospital, London, between January 1991 and April 2012. In 13 patients with bilateral AK, 1 eye was randomly excluded from analysis. METHODS: Patient demographics and clinical examination findings were collected both at the start of AAT and subsequently at the time that topical corticosteroid therapy was initiated. Preliminary a priori investigations were used to identify effect modifiers/confounders and extreme associations requiring consideration in multivariate regression modeling. A multivariable logistic model, optimized for assessment of corticosteroid use after the start of AAT, was used to estimate the odds ratios (ORs) of a suboptimal outcome. MAIN OUTCOME MEASURES: Suboptimal outcome was defined as final visual acuity ≤20/80, corneal perforation, or the need for keratoplasty. RESULTS: In multivariable analysis, restricted to 129 eyes (1 eye per patient) free of scleritis and hypopyon at the start of AAT, topical corticosteroids were not associated with worse outcomes (OR, 1.08; 95% confidence interval [CI], 0.39-3.03), even when corticosteroids had been used before the start of AAT. Risk factors significantly associated with worse outcomes were topical corticosteroid use before the start of AAT (OR, 3.85; 95% CI, 1.35-11.03), a corneal ring infiltrate (together with at least 1 other feature of AK) present at the start of AAT (OR, 5.89; 95% CI, 1.17-29.67), and age ≥33 years at the start of AAT (OR, 4.02; 95% CI, 1.46-11.06). CONCLUSIONS: Many corneal specialists currently are uncertain about the risk benefit associated with the use of topical corticosteroids for the management of inflammatory complications of AK. The evidence from this study gives clinicians and patients reassurance that the potential benefits of topical corticosteroid therapy, for treating pain and discomfort, are not associated with worse outcomes when initiated after starting modern AAT. Other potential benefits, in terms of resolution of inflammatory complications, will not be demonstrated without a carefully designed randomized clinical trial.

[Diagnosis of Acanthamoeba keratitis]. / Diagnostika akantamebnogo keratita.

The Acanthamoeba keratitis is a relatively rare, but dangerous disease of the cornea. Its development is thought to be associated with contact lens wearing as well as corneal microwounds contaminated with soil or water. The disease has no evident distinctive clinical features and is, therefore, difficult to be distinguished from herpetic or fungal keratitis. Nevertheless, Acanthamoeba infection can be suspected judging from anamnestic data (i.e. contact lens use and corneal injury with subsequent contamination of the wound), inadequately strong pain syndrome, ring-shaped infiltration of the cornea and ineffectiveness of conventional therapy. Also helpful may be such measures as isolating the bacteria using the method of biocultures, morphological examination of corneal biopsy material (using light and luminescent microscopy), genetic testing, and in vivo confocal microscopy of the cornea. Other promising methods are also listed in this article. A widely accepted diagnostic technique is yet, however, missing.

Therapeutic and optical keratoplasty in the management of Acanthamoeba keratitis: risk factors, outcomes, and summary of the literature.

OBJECTIVE: To report the risk factors for and outcomes of therapeutic and optical keratoplasty in the management of Acanthamoeba keratitis (AK). DESIGN: Retrospective case series. PARTICIPANTS: A total of 50 eyes of 196 patients with retrievable medical records, diagnosed with AK at Moorfields Eye Hospital, London, underwent keratoplasty between January 1991 and April 2012. METHODS: Patient demographics, initial clinical examination findings, and management details were collected. The ophthalmic characteristics of patients who underwent keratoplasty for AK were compared with those who did not. Patients undergoing therapeutic keratoplasty were compared with those undergoing optical keratoplasty for baseline characteristics, management details, and visual outcomes. A multivariate logistic model was used to derive the odds ratios of a poor visual outcome in all keratoplasty patients. MAIN OUTCOME MEASURES: Poor visual outcome was defined as final visual acuity of 20/200 or worse. Secondary outcomes of interest included number of clinic visits and the need for additional intraocular surgery. RESULTS: Of the 196 AK patients, a total of 50 patients (25.5%) underwent penetrating or anterior lamellar keratoplasty, 10 of whom (20%) underwent repeat procedures. Of these 50 patients, 26 (52%) had therapeutic keratoplasty, predominantly for corneal perforation. The remaining 24 patients (48%) underwent optical keratoplasty for visual rehabilitation. Thirty-seven (80.4%) patients in the keratoplasty group initially were misdiagnosed as having herpes simplex keratitis versus 59 (41.8%) patients who did not require a keratoplasty (P < 0.001). Final visual outcomes were significantly better in the optical group compared with the therapeutic group, with 13 (54.2%) achieving visual acuity of 20/30 or better versus 7 (26.9%), respectively. On multivariate analysis, beginning therapy at a hospital other than Moorfields and undergoing a therapeutic, rather than an optical, keratoplasty were associated significantly with a poor visual outcome from keratoplasty. CONCLUSIONS: The prognosis of keratoplasty differs markedly when performed for therapeutic purposes compared with visual rehabilitation. Where possible, keratoplasty should be delayed until such time as the eye is uninflamed and medically cured of Acanthamoeba.

Treatment of acanthamoeba keratitis with intravenous pentamidine before therapeutic keratoplasty.

PURPOSE: The aim of this study was to evaluate the outcome of pretreatment of Acanthamoeba keratitis with intravenous pentamidine (IVP) before therapeutic keratoplasty (TKP). METHODS: A retrospective chart review was performed of the medical records of every patient treated with IVP before TKP for Acanthamoeba keratitis at a single, tertiary care eye center between January 1, 2002, and December 31, 2012. The main outcome measures were microbiological cure, graft survival, and visual outcome. RESULTS: Eight eyes of 7 patients met the inclusion criteria. Preoperatively, all 8 eyes had failed traditional antiamoebic therapy, including 5 eyes with recurrent infections after previous TKP. The patients were treated with IVP (190-400 mg/d) for a median of 14 days (range, 7-26 days). After 8 TKP, a microbiological cure was achieved, and a clear graft was maintained in 5 (62.5%) eyes during a mean follow-up interval of 31.2 months (range, 1.0-95.7 months). Repeat TKP in 3 eyes with recurrent Acanthamoeba keratitis resulted in 2 additional microbiological cures and 1 more clear graft. The final best-corrected visual acuity was ≥20/40 in 5 (62.5%) eyes and worse than 20/200 in 3 eyes. Overall, the final vision was improved in 6 (75.0%) eyes, remained the same in 1 (12.5%) eye, and was worse in 1 (12.5%) eye. CONCLUSIONS: The adjunctive use of IVP before TKP may assist with the achievement of microbiological cure, clear graft, and good visual outcome in a majority of eyes with Acanthamoeba keratitis.

Current advances in diagnostic methods of Acanthamoeba keratitis.

OBJECTIVE: The objective of this article was to review the current advances in diagnostic methods for Acanthamoeba keratitis (AK). DATA SOURCES: Data used in this review were retrieved from PubMed (1970-2013). The terms "Acanthamoeba keratitis" and "diagnosis" were used for the literature search. STUDY SELECTION: Data from published articles regarding AK and diagnosis in clinical trials were identified and reviewed. RESULTS: The diagnostic methods for the eight species implicated in AK were reviewed. Among all diagnostic procedures, corneal scraping and smear examination was an essential diagnostic method. Polymerase chain reaction was the most sensitive and accurate detection method. Culturing of Acanthamoeba was a reliable method for final diagnosis of AK. Confocal microscopy to detect Acanthamoeba was also effective, without any invasive procedure, and was helpful in the early diagnosis of AK. CONCLUSION: Clinically, conjunction of various diagnostic methods to diagnose AK was necessary.

[Acanthamoeba keratitis]. / Kératites amibiennes.

Early diagnosis and appropriate therapy are key elements for a good prognosis in Acanthamoeba keratitis (AK). AK should be considered in any case of corneal trauma complicated by exposure to soil or contaminated water, and in all contact lens (CL) wearers. A presumptive diagnosis of AK can be made clinically and with in vivo confocal microscopy, although a definitive diagnosis requires identification of Acanthamoeba on direct scraping, histology, or identification of Acanthamoeba DNA by polymerase chain reaction (PCR). We use cysticidal drugs for treating AK because encysted forms are more resistant than trophozoites to treatment. The treatment protocol used a biguanide (PHMB 0.02% or chlorhexidine 0.02%) and a diamidine (propamidine 0.1% or hexamidine 0.1%). New diagnostic modalities and more specific topical anti-amoebic treatments would substantially benefit patients with AK.

Clinical features of Acanthamoeba keratitis in contact lens wearers and non-wearers.

Clinical presentations of patients with Acanthamoeba keratitis (AK) attending the Faculty of Medicine Siriraj Hospital during 1996-2006 were reviewed. The studied parameters included history of ocular trauma, use of contact lenses, associated eye diseases, systemic diseases, visual acuity, symptoms, signs, treatment, visual outcomes, and sequelae. Data were analyzed by comparing non-contact lens (nCL) and contact lens (CL) wearers with eachother. Twenty-two patients (24 affected eyes) (68.2% female) had AK, 9 (37.5%) were nCL and 15 (62.5%) were CL. Both groups had similar basic characteristics; however the nCL group was significantly older (48.3 +/- 14.5 vs 30.6 +/- 15.3 years old, p=0.006), and tended to have a longer duration of symptoms with more severe clinical findings, but this was not statistically significant. Eleven had severe ciliary injection (nCL 55.5%, CL 40.0%), 3 had satellite lesions (nCL 22.2%, CL 6.7%), 2 had radial keratoneuritis in the CL group (13.3%), 1 ring infillrate in the nCL group (11.1%) and 1 pseudodendrite in the CL group (6.7%). The mean duration of follow-up was 8.2 +/- 7.9 (ranging 0.3-29) months. Therapeutic measures included anti-Acanthamoeba medications (5/9 for nCL, 8/15 for CL), penetrating keratoplasty due to uncontrolled infections (1/9 for nCL, 2/15 for CL) and corneal perforation (1/9 for nCL), and enucleation due to endophthalmitis (1/9 for CL). At the last follow-up visit, the CL [corrected] group had slightly better visual acuity (55.5% vs 66.7%). In conclusion, AK among patients who do not use contact lenses may have a delayed diagnosis, resulted in more severe ocular manifestations and poorer prognosis. Physicians should be aware of Acanthamoeba infection as a cause of keratitis in any patient, not just contact lens wearers. Long periods of follow-up are recommended to observe for recurrent episodes and proper management of AK patients.

Prognostic factors in Acanthamoeba keratitis.

OBJECTIVE: To assess the prognostic factors influencing visual prognosis and length of treatment after acanthamoeba keratitis (AK). PARTICIPANTS: Forty-two AK eyes of 41 patients treated between 1999 and 2006 were included. METHODS: A diagnosis of AK was made on the basis of culture results with a corresponding clinical presentation. We calculated the prognostic effect of the various factors on final visual acuity and the length of treatment. Multivariate regression analysis was used to adjust for the simultaneous effects of the various prognostic factors. RESULTS: Mean follow-up was 19.7 ± 21.0 months. Sixty-four percent of cases had > 1 identified risk factor for AK, the most common risk factor being contact lens wear (92.9% of eyes). At presentation, median best spectacle corrected visual acuity (BCVA) was 20/200 (20/30 to Hand Motion [HM]) that improved after treatment to 20/50 (20/20 to Counting Fingers [CF]). Infection acquired by swimming or related to contact lenses had significantly better final BCVA (p = 0.03 and p = 0.007, respectively). Neuritis and pseudodendrites were also associated with better final BCVA (p = 0.04 and p = 0.05, respectively). Having had an epithelial defect on presentation and having been treated with topical steroid were associated with worse final best spectacle corrected visual acuity (BSCVA) (p = 0.0006 and p = 0.04). Multivariate regression analysis found a good initial visual acuity (p = 0.002), infections related to swimming (p = 0.01), the absence of an epithelial defect (p = 0.03), having been treated with chlorhexidine (p = 0.05), and not having receive steroids (p = 0.003) to significantly forecast a good final BCVA. CONCLUSIONS: We identified several prognostic factors that can help clinicians evaluate the expected visual damage of the AK infection and thus tailor treatment accordingly.