Cases Of Acanthamoeba Keratitis Research Articles

Understanding Acanthamoeba Keratitis: An In-Depth Review of a Sight-Threatening Eye Infection.

Acanthamoeba keratitis (AK) is a rare but potentially sight-threatening corneal infection caused by the Acanthamoeba parasite. This microorganism is found ubiquitously in the environment, often in freshwater, soil, and other sources of moisture. Despite its low incidence, AK presents significant challenges due to delayed diagnosis and the complex nature of therapeutic management. Early recognition is crucial to prevent severe ocular complications, including corneal ulceration and vision loss. Diagnostic modalities and treatment strategies may vary greatly depending on the clinical manifestation and the available tools. With the growing reported cases of Acanthamoeba keratitis, it is essential for the ophthalmic community to thoroughly understand this condition for its effective management and improved outcomes. This review provides a comprehensive overview of AK, encompassing its epidemiology, risk factors, pathophysiology, clinical manifestations, diagnosis, and treatment.

Clinical outcomes and prognostic factors in Acanthamoeba keratitis

PurposeTo report clinical findings and prognostic factors for visual and morphological outcomes in patients with Acanthamoeba keratitis (AK). MethodsSingle-center, retrospective, longitudinal study of 51 cases of AK diagnosed by real-time polymerase chain reaction (RT-PCR) between March 2010 and October 2022. The primary outcome was the final best corrected visual acuity (BCVA). Poor visual outcome was defined as a final BCVA ≥ 1 logMAR unit, while good visual outcome was defined as a final BCVA < 1 logMAR unit. Eyes from these two groups were compared, regarding demographic and initial clinical variables, anti-Acanthamoeba treatment used, and complications of the disease. Early diagnosis was defined as ≤ 14 days from symptom onset to diagnostic confirmation and initiation of Acanthamoeba medical treatment. Multivariable logistic regression was used to determine predictors of poor visual outcome. ResultsA total of 51 eyes from 46 patients diagnosed with AK, all contact lens (CL) wearers, were included in this study. Average follow-up was 39.0 ± 30.2 [total range 14–120] months. Thirty-one eyes (60.8 %) presented good visual outcome, with a lower baseline age (30.5 ± 9.0 vs. 42.3 ± 15.8; p = 0.020), better initial BCVA (0.8 ± 0.7 logMAR units vs. 1.3 ± 0.9 logMAR units; p = 0.047), higher rate of early diagnosis (45.2 % vs. 5.6 %; p = 0.004), and higher rate of therapeutic epithelial debridement (64.5 % vs. 10 %; p < 0.001). 20 eyes (39.2 %) presented poor visual outcome, with 12 eyes undergoing evisceration/enucleation (23.5 %). These 20 eyes presented a higher rate of complications (90 % vs. 61.3 %; p = 0.031). In multivariable analysis, early diagnosis of AK (OR 19.78; 95 % CI 2.07–189.11; p = 0.010) and therapeutic epithelial debridement (OR 19.02; 95 % CI 3.27–110.57; p = 0.001) were associated with a good visual outcome. ConclusionsIn the present study, poor visual outcome was present in 39 % of affected eyes. Early AK diagnosis (≤14 days from symptom onset) and therapeutic epithelial debridement were associated with good final visual outcome.

Differentiation of acanthamoeba keratitis from other non-acanthamoeba keratitis: Risk factors and clinical features.

Infectious Keratitis is one of the most common ocular emergencies seen by ophthalmologists. Our aim is to identify the risk factors and clinical features of Acanthamoeba Keratitis (AK). This retrospective chart review study was conducted at King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia, and included all the microbial keratitis cases, male and female patients of all ages. The main outcome is the differentiation between various microbial keratitis types. We included 134 consecutive eyes of 126 persons. We had 24 cases of acanthamoeba keratitis, 22 bacterial keratitis, 24 fungal keratitis, 32 herpetic keratitis, and 32 bacterial co-infection. Contact lens wear was found in 33 eyes (24.6%). Among acanthamoeba keratitis patients, 73% were ≤ 39 years of age, and 73% were females (P <0.001). Also, in AK cases, epithelial defect was found in all cases (100%), endothelial plaques were found in 18 eyes (69.2%), 12 cases had radial keratoneuritis (46.2%), and ring infiltrate was found in 53.8% of AK cases. We determined the factors that increase the risk of acanthamoeba infection and the clinical characteristics that help distinguish it from other types of microbial keratitis. Our findings suggest that younger females and patients who wear contact lenses are more likely to develop acanthamoeba keratitis. The occurrence of epitheliopathy, ring infiltrate, radial keratoneuritis, and endothelial plaques indicate the possibility of acanthamoeba infection. Promoting education on wearing contact lenses is essential to reduce the risk of acanthamoeba infection, as it is the most significant risk factor for this infection.

Use of In Vivo Corneal Confocal Microscopy to Guide Excimer Laser With Adjunctive Mitomycin C for Treatment of Recalcitrant Acanthamoeba Keratitis.

The aim of this study was to describe 3 cases of recalcitrant Acanthamoeba keratitis (AK) that were successfully treated using in vivo corneal confocal microscopy (IVCM) to guide excimer laser ablation depth with adjunctive mitomycin C 0.02%. Three patients diagnosed with AK did not respond to several weeks of intensive topical therapy with antiamoebic agents. The patient underwent phototherapeutic keratectomy with topical mitomycin C 0.02% application. The maximum stromal depth of cysts measured by IVCM was 80 μm, 100 μm, and 240 μm, and the stromal ablation depths were 80 μm, 100 μm, and 100 μm, respectively. In all 3 eyes, AK resolved after a single excimer laser application, and topical treatment was gradually discontinued within 6 weeks afterward. In 1 eye, penetrating corneal transplantation was performed 6 weeks after phototherapeutic keratectomy because of ongoing severe corneal pain. IVCM and histology of the corneal transplant did not reveal any Acanthamoeba cysts within the excised corneal button. No recurrence was observed during the follow-up period of 19 to 34 months. IVCM-guided phototherapeutic keratectomy with mitomycin C 0.02% seems to be a safe and successful approach for the treatment of AK, especially in cases of resistance to topical treatment. Corneal IVCM should be performed before laser application to measure cyst depth, determine ablation depth, and assess postoperative treatment success.

Improving polymerase chain reaction diagnostic rates for herpes simplex keratitis: results of a pilot study.

Laboratory confirmation is crucial for diagnosis and management of herpes simplex virus (HSV) keratitis. However, the sensitivity of polymerase chain reaction (PCR) in keratitis is low (25%) compared with that of mucocutaneous disease (75%). We developed an educational intervention aimed at improving the diagnostic yield of PCR. The medical records of keratitis cases seen at the emergency department of a London tertiary ophthalmic referral hospital over two distinct periods, before and after an educational program on swab technique, were reviewed retrospectively. A total of 252 HSV cases were included. Increases in the laboratory-confirmed diagnosis of HSV-1 were observed, in both first presentations (11.1%-57.7%) and recurrent cases (20%-57.6%). The rate of positive HSV-1 PCR in eyes with an epithelial defect increased from 19% pre-intervention to 62% post intervention. Notably, 3% were positive for varicella zoster virus DNA, and there was a single case of Acanthamoeba keratitis. Our results suggest that, with proper swabbing technique, PCR may be more sensitive than previously reported.

The global incidence and prevalence of Acanthamoeba keratitis

Aims/Purpose: To assess the global incidence and prevalence of Acanthamoeba keratitis (AK).Methods: The review protocol was prospectively registered in PROSPERO (CRD42022363243) and the Cochrane Handbook was followed in the conduction of the analysis. The study included male and female participants worldwide (&gt;15 years old). PubMed, Scopus, Web of Science, EMBASE, and CINHAL were the sources of data. The incidence of AK was determined by calculating the number of cases per centre per year, while the prevalence was evaluated for the entire population and the entire population of patients with non‐viral infectious keratitis. Based on the population prospects of the United Nations, actual and provisional estimates of the global epidemiological burden of AK, covering a period of up to 50 years, were provided.Results: A total of 134 articles were included in the analysis. The analysis revealed a median incidence of 2.42 (95% CI: 1.67, 3.8) new cases of AK per centre per year, without any statistically significant difference among the continents (p = 0.1411). The percentage of AK cases within the total number of MK cases was found to be 1.62% (95% CI: 1.51, 1.74). Using a random effect model, the prevalence of AK in relation to the entire population was estimated to be 0.0003% (95% CI: 0.0001; 0.0006). The projected increase in the total and provisional numbers of AK cases indicates a rise of 20.4% (2003 AK cases) in 2053 and 24.8% (2076 AK cases) in 2073, compared to the baseline of 2023 (1663 AK cases).Conclusions: Although rare, AK is a significant condition that is projected to increase in prevalence by up to 24% over the next 50 years.

Incidence of Acanthamoeba Keratitis in the United Kingdom in 2015: A Prospective National Survey.

The aims of this study were to quantify the incidence of Acanthamoeba keratitis (AK) in the United Kingdom and investigate risk factors and management parameters. This was a prospective population-based study from January to December 2015 through the British Ophthalmic Surveillance Unit. Data were collected on demographics, clinical features, and management. Incidence rates were calculated from estimates of population and contact lens (CL) user numbers. Statistical analysis compared annualized incidences per million and altered risk ratios for AK with the England and Wales 24 months 1997/1998 to 1998/1999 study. The study identified 124 AK cases, an overall incidence of 2.35 per million. CL wearers accounted for 108 of 124 cases (87%), in whom the AK incidence was 26.94 per million. Herpes keratitis was initially misdiagnosed in 25 of 124 cases (20.2%). The highest incidence of AK was among planned replacement soft CL (PRSCL) wearers (50.65 per million), 7-fold greater than for daily disposable CL (DDSCL) users (7.24 per million). There was a significant increase in AK incidence ( P < 0.001) compared with both 1997/1998 [risk ratio 1.92, 95% confidence interval (CI) 1.38-2.66] and 1998/1999 (risk ratio 2.13, 95% CI 1.52-2.98) together with a higher incidence per million CL users of 26.94 versus 21.14 (1997/1998) and 17.53 (1998/1999). This study provides the first published data on the nationwide incidence of AK in the United Kingdom. The findings confirm an increasing incidence of AK, particularly among contact lens wearers since 1997/1998 to 1998/1999. PRSCLs were identified as a significant risk factor compared with DDSCLs. Misdiagnosis and treatment delays remain an ongoing problem for patients with AK.

Seasonal and Temporal Trends of Infectious Keratitis in Northern Vietnam.

The epidemiology of corneal ulcers in Vietnam has not been well characterized. In this report, we reviewed retrospectively the microbiological data of patients with a clinical diagnosis of corneal ulcer at the microbiology laboratory of Vietnam National Eye Hospital from January 1, 2010 to March 31, 2023. We observed a seasonal pattern for fungal and microsporidial keratitis, with an annual peak in November, and an inverse relationship between fungal keratitis and inclement weather. The November peak coincided with one of the major harvesting seasons in Vietnam. We also observed increasing numbers of microsporidial and Acanthamoeba keratitis cases in recent years. Knowledge of these trends are helpful in guiding empirical treatment of corneal infections and preventing corneal blindness.

AI-Based Decision-Support System for Diagnosing Acanthamoeba Keratitis Using In Vivo Confocal Microscopy Images.

In vivo confocal microscopy (IVCM) of the cornea is a valuable tool for clinical assessment of the cornea but does not provide stand-alone diagnostic support. The aim of this work was to develop an artificial intelligence (AI)-based decision-support system (DSS) for automated diagnosis of Acanthamoeba keratitis (AK) using IVCM images. The automated workflow for the AI-based DSS was defined and implemented using deep learning models, image processing techniques, rule-based decisions, and valuable input from domain experts. The models were evaluated with 5-fold-cross validation on a dataset of 85 patients (47,734 IVCM images from healthy, AK, and other disease cases) collected at a single eye clinic in Sweden. The developed DSS was validated on an additional 26 patients (21,236 images). Overall, the DSS uses as input raw unprocessed IVCM image data, successfully separates artefacts from true images (93% accuracy), then classifies the remaining images by their corneal layer (90% accuracy). The DSS subsequently predicts if the cornea is healthy or diseased (95% model accuracy). In disease cases, the DSS detects images with AK signs with 84% accuracy, and further localizes the regions of diagnostic value with 76.5% accuracy. The proposed AI-based DSS can automatically and accurately preprocess IVCM images (separating artefacts and sorting images into corneal layers) which decreases screening time. The accuracy of AK detection using raw IVCM images must be further explored and improved. The proposed automated DSS for experienced specialists assists in diagnosing AK using IVCM images.

Isolation and molecular characterization of Acanthamoeba spp. from Iraqi patients with Keratitis

Isolation and molecular characterization of Acanthamoeba spp. related corneal infections in Iraqi Patients. A total of 96 samples from corneal scraps and contact lenses were gathered from corneal patients for the current trial, which runs from November 2020 to May 2021. All plates were checked, classifying them as positive or negative morphologically identification of Acanthamoeba spp. where PCR analysis, which entails the targeted amplification of nucleic acids, has been carried out, and where The 18s rRNA gene's DF3 region was the focus of the isolated strains' sequences. Three patients had Acanthamoeba spp. infections, according to the findings. then the sequence analysis was performed using the NCBI tool, which showed the presence of 2 different genotypes, two strains were grouped into the T3 genotype, one from T4, then they were registered in GeneBank under number accession (MZ427912, MZ349042) respectively. To our knowledge, these are the first reported cases of Acanthamoeba keratitis in Iraq.

Imidazolium ionic liquid as potential contact lens disinfectant inactivating cystic resistance forms from ACANTHAMOEBA keratitis

Keratitis caused by Acanthamoeba spp. is a rare disease, although increasingly common, especially among contact lens users. The occurrence and the devastating effect of this disease are associated with the lack of care in cleaning and disinfecting lenses and their storage cases, as well as ineffective drugs to mainly eliminate the parasite’s cysts. This work evaluated the amoebicidal activity of the imidazolium salt 1-hexadecyl-3-methylimidazolium chloride (C16MImCl) against cysts of two characterized isolates from Acanthamoeba keratitis cases (MZ404337 and MZ404332). The inactivation of 100% of the cysts was achieved at a concentration of 7.81 μg/mL for MZ404337 and of 1.95 μg/mL for MZ404332, both at 24 h and 48 h of exposure time. In contrast, a commercial formulation of chlorhexidine did not cause any reduction in the viability of the cysts. Related to the cytotoxicity to human HaCaT cells, C16MImCl is biocompatible at the concentration required to inactivate cysts. This shows that C16MImCl is a promising disinfectant for contact lenses and surfaces. KEY WORDS: 1-hexadecyl-3-methylimidazolium chloride; Acanthamoeba keratitis; cysts; chlorhexidine; cytotoxicity.

A 5-Year Review of Coinfections in Acanthamoeba keratitis From South India.

To ascertain the frequency of coinfections in Acanthamoeba keratitis, the nature of copathogens involved, and to analyze the implications in the context of current research on amoebic interactions. A retrospective case review from a Tertiary Care Eye Hospital in South India. Smear and culture data for coinfections in Acanthamoeba corneal ulcers were collected from records over a 5-year period. The significance and relevance of our findings in the light of current research on Acanthamoeba interactions were analyzed. Eighty-five cases of culture-positive Acanthamoeba keratitis were identified over a 5-year period (43 of them being coinfections). Fusarium was most commonly identified species, followed by Aspergillus and the dematiaceous fungi. Pseudomonas spp was the commonest bacterial isolate. Coinfections with Acanthamoeba are common at our centre, and account for 50% of Acanthamoeba keratitis. The diverse nature of the organisms involved in coinfections suggest that such amoebic interactions with other organisms are probably more widespread than recognized. To the best of our knowledge, this is the first documentation from a long-term study of pathogen diversity in Acanthamoeba coinfections. It is possible that Acanthamoeba itself may be virulence enhanced and secondary to the co-organism, breaching the ocular surface defenses in an already compromised cornea. However, observations from the existing literature on Acanthamoeba interactions with bacteria and certain fungi are based mainly on nonocular or nonclinical isolates. It would be illuminating if such studies are performed on Acanthamoeba and coinfectors from corneal ulcers-to ascertain whether interactions are endosymbiotic or virulence enhanced through amoebic passage.

Twenty‐five years of acanthamoeba diagnostics in Austria

AbstractAcanthamoeba spp. are ubiquitous free‐living amoebae and do not need a host. They can, however, cause disease upon accidental contact with a potential host. The most common Acanthamoeba infection in humans is the so‐called Acanthamoeba keratitis (AK), occurring mainly in contact lens wearers.The first case of AK was reported in the early seventies and in the mid‐eighties the association between AK and contact lens wear was discovered. Today, acanthamoebae are among the most important causative agents of keratitis in contact lens wearers. AK often shows a severe progression, which is due to a lack of awareness but also to the lack of specific treatment. The dormant cysts pose a particular problem, often residing within the tissue and leading to reinfection after termination of treatment. In industrialized countries the annual incidence of AK lies between 0.1–1 cases per 100 000 inhabitants, with a marked regional variation depending on contact lens wear habits and mode of water supply.Our institution is the Austrian reference laboratory for Acanthamoeba diagnostics. All samples from patients with suspected AK are screened for Acanthamoeba spp. by culture and PCR in parallel, and all detected amoebae are genotyped. We currently have an annual incidence of AK of around 0.2 cases per 100 000 inhabitants, with &gt;90% of cases occurring in contact lens wearers. In contrast to other countries, we do not see any seasonality and in contrast to the early years, today, males and females are equally represented, the most affected group being the 21–30‐year‐olds. The vast majority of cases are unilateral and many cases have a prolonged progression, in some cases infections remain viable for &gt;1 yr. The predominant genotype is Acanthamoeba T4, other common genotypes are T3, T5, T6, T10 and T11.

Utility of In Vivo Confocal Microscopy in Diagnosis of Acanthamoeba Keratitis: A Comparison of Patient Outcomes.

The aim of this study was to compare outcomes between cases of Acanthamoeba keratitis (AK) diagnosed and treated with or without the use of in vivo confocal microscopy (IVCM). We performed a retrospective comparative case series of 26 eyes of 23 patients diagnosed with AK at the Massachusetts Eye and Ear Infirmary over a 5-year period. The characteristics of all identified cases were summarized. We compared the time from presentation to diagnosis of AK (primary outcome), visual acuity, and rates of therapeutic penetrating keratoplasty between eyes diagnosed by culture-only group (n = 8) and by IVCM to diagnose AK (n = 9) and later confirmed by culture (IVCM/C group). The diagnostic delay was significantly longer in the culture only group (25 ± 29 days) compared with the IVCM/C group (3 ± 3 days, P < 0.01). At 6 months, there was a significant difference in best-corrected visual acuity between the culture-only group (1.46 ± 1.07, n = 7) and the IVCM/C group (0.22 ± 0.22, n = 8), after adjusting for initial baseline visual acuity (P = 0.02). Therapeutic penetrating keratoplasty was performed in 50% of culture-only (n = 7) and 11% of IVCM/C group eyes (n = 9), but this was not statistically significant (P = 0.13). IVCM can expedite the diagnosis of AK, and its use as an adjunct tool in the diagnosis of AK may result in better patient outcomes compared with basing treatment decisions on corneal cultures alone.

Assessment of genotypes, endosymbionts and clinical characteristics of Acanthamoeba recovered from ocular infection

IntroductionAcanthamoeba is an emerging pathogen, infamous for its resilience against antiprotozoal compounds, disinfectants and harsh environments. It is known to cause keratitis, a sight-threatening, painful and difficult to treat corneal infection which is often reported among contact lens wearers and patients with ocular trauma. Acanthamoeba comprises over 24 species and currently 23 genotypes (T1-T23) have been identified.AimsThis retrospective study was designed to examine the Acanthamoeba species and genotypes recovered from patients with Acanthamoeba keratitis (AK), determine the presence of endosymbionts in ocular isolates of Acanthamoeba and review the clinical presentations.MethodologyThirteen culture-confirmed AK patients treated in a tertiary eye care facility in Hyderabad, India from February to October 2020 were included in this study. The clinical manifestations, medications and visual outcomes of all patients were obtained from medical records. The Acanthamoeba isolates were identified by sequencing the ribosomal nuclear subunit (rns) gene. Acanthamoeba isolates were assessed for the presence of bacterial or fungal endosymbionts using molecular assays, PCR and fluorescence in situ hybridization (FISH).ResultsThe mean age of the patients was 33 years (SD ± 17.4; 95% CI 22.5 to 43.5 years). Six (46.2%) cases had AK associated risk factors; four patients had ocular trauma and two were contact lens wearers. A. culbertsoni (6/13, 46.2%) was the most common species, followed by A. polyphaga and A. triangularis. Most of the isolates (12/13) belonged to genotype T4 and one was a T12; three sub-clusters T4A, T4B, and T4F were identified within the T4 genotype. There was no significant association between Acanthamoeba types and clinical outcomes. Eight (61.5%) isolates harboured intracellular bacteria and one contained Malassezia restricta. The presence of intracellular microbes was associated with a higher proportion of stromal infiltrates (88.9%, 8/9), epithelial defect (55.6%, 5/9) and hypopyon (55.6%, 5/9) compared to 50% (2/4), 25% (1/4) and 25% (1/4) AK cases without intracellular microbes, respectively.ConclusionsGenotype T4 was the predominant isolate in southern India. This is the second report of T12 genotype identified from AK patient in India, which is rarely reported worldwide. The majority of the Acanthamoeba clinical isolates in this study harboured intracellular microbes, which may impact clinical characteristics of AK.

Acanthamoeba Keratitis Risk Factors for Daily Wear Contact Lens Users: A Case–Control Study

This study was designed to establish risk factors for the development of Acanthamoeba keratitis (AK) for daily disposable (DD) contact lens (CL) users compared with daily wear (DW) reusable lens users and for risks unique to DD users. This is important because, in many major economies, CL use is the principal cause of microbial keratitis, of which AK accounts for approximately 50% of cases with sight loss. Determining these AK risks informs practitioner advice and consumer behavior. Case-control study. Cases and controls were recruited from an Accident and Emergency Department serving South-East England. Cases were new CL users with AK recruited retrospectively from January 2011 to February 2013 and prospectively thereafter until August 2014. Controls were recruited prospectively from February 2014 to June2015. Analysis of a self-administered questionnaire. Independent risk factors and population attributable risk percentage (PAR%) for AK. A total of 83 AK cases and 122 controls were recruited; DD use was reported by 20 (24%) cases and 66 (54%) controls. In multivariable analyses adjusted for potential confounders, the odds of AK was higher for DW reusable soft lenses (odds ratio [OR], 3.84; 95% confidence interval [CI], 1.75-8.43) and rigid lenses (OR, 4.56; 95% CI, 1.03-20.19) than for DD lenses. Within the DD-using subset, AK was associated with the following modifiable risk factors: less frequent professional follow-up visits (OR, 10.12; 95% CI, 5.01-20.46); showering in lenses (OR, 3.29, 95% CI, 1.17-9.23); lens reuse (OR, 5.41; 95% CI, 1.55-18.89); and overnight wear (OR, 3.93; 95% CI, 1.15-13.46). The PAR% estimated that 30% to 62% of cases could be prevented by switching from reusable soft lens to DD lens use. Acanthamoeba keratitis risks are increased > threefold in DW reusable lens users versus DD lens use. Acanthamoeba keratitis risks for DD lens users can be minimized by adherence to safe use guidelines (no reuse, overnight wear, or contamination by water). Safe CL use can be improved by increasing the prominence of risk avoidance information from manufacturers and regulators. Because AK accounts for half of severe keratitis in CL users, these measures can be expected to have public health benefits.

Diagnosis and Management of Acanthamoeba Keratitis: A Continental Approach

Acanthamoeba keratitis (AK) is a potentially blinding infection caused by protozoa found worldwide. The topical application of biguanides and diamidines is the most common anti-amoebic treatment for AK. In this study, we hypothesized that geographical location and socioeconomic status influence the management and treatment of AK. To test this hypothesis, we analyzed case reports and series of Acanthamoeba eye infections from different geographic regions to evaluate the association between diagnosis, treatment, and outcome worldwide. This study looked specifically at case reports of patients with diagnosed AK using bibliographic databases such as PubMed, BioMed Central, and Google Scholar, which were searched between 30 April 1990 and 1 May 2022. The search identified 38 eligible studies that provided data for 60 clinical cases of AK. The results indicated that current standard treatments are effective if the infection is identified early and that delays can lead to clinical symptoms, including permanent visual opacities. There was evidence suggesting an association between the treatment regimen practiced in certain geographic regions and treatment outcome. Patient access to medical facilities and economic background also had an influence on the treatment and outcome of AK. Further analysis of more case reports can expand our understanding of the influence of specific demographic and individual patient characteristics on the effectiveness and accessibility of AK medicines. Additionally, using a living systematic review approach to incorporate emerging evidence will reveal the relative merits of different treatment regimens for AK and outcomes.

Acanthamoeba Keratitis After Corneal Refractive Surgery: A Case Series and Literature Review

PURPOSE: To report three cases with Acanthamoeba keratitis after laser vision correction and their treatment course and outcomes, and to compare these with the existing literature. METHODS: Case series and literature review. RESULTS: Three eyes of three patients presented with Acanthamoeba keratitis after laser vision correction and were treated with a high concentration of anti-amoebic medication after a timely diagnosis. In the first case, which occurred after laser in situ keratomileusis, there was an excellent recovery 1 month after treatment. In the second case, the uncorrected distance visual acuity (UDVA) after laser-assisted subepithelial keratectomy (LASEK) returned to 8/20 after similar anti-amoebic treatment, but for a period of 4 months. Despite using the same treatment regimen, the third case of Acanthamoeba keratitis after LASEK required a penetrating keratoplasty. This was deemed necessary because the cornea was completely infiltrated. There was no recurrence of the infection and the UDVA achieved 6 months postoperatively was 4/20. CONCLUSIONS: Early diagnosis and standardized postoperative management is the top priority in Acanthamoeba keratitis after laser vision correction. Glucocorticoids should stop when the infection is suspected and Acanthamoeba keratitis should always be considered, particularly when pain is severe and standard antibiotics fail. Intensive anti-amoebic treatment in the early period and judicious use of penetrating keratoplasty in Acanthamoeba keratitis after laser vision correction may benefit prognosis. [ Journal of Refractive Surgery Case Reports. 2022;2(2):e32–e37.]

Tannic Acid-Modified Silver Nanoparticles in Conjunction with Contact Lens Solutions Are Useful for Progress against the Adhesion of Acanthamoeba spp. to Contact Lenses.

Acanthamoeba spp. are amphizoic amoebae that are widely distributed in the environment and capable of entering the human body. They can cause pathogenic effects in different tissues and organs, including Acanthamoeba keratitis (AK), which may result in a loss of visual acuity and blindness. The diagnostics, treatment, and prevention of AK are still challenging. More than 90% of AK cases are related to the irresponsible wearing of contact lenses. However, even proper lens care does not sufficiently protect against this eye disease, as amoebae have been also found in contact lens solutions and contact lens storage containers. The adhesion of the amoebae to the contact lens surface is the first step in developing this eye infection. To limit the incidence of AK, it is important to enhance the anti-adhesive activity of the most popular contact lens solutions. Currently, silver nanoparticles (AgNPs) are used as modern antimicrobial agents. Their effectiveness against Acanthamoeba spp., especially with the addition of plant metabolites, such as tannic acid, has been confirmed. Here, we present the results of our further studies on the anti-adhesion potential of tannic acid-modified silver nanoparticles (AgTANPs) in combination with selected contact lens solutions against Acanthamoeba spp. on four groups of contact lenses. The obtained results showed an increased anti-adhesion activity of contact lens solutions in conjunction with AgTANPs with a limited cytotoxicity effect compared to contact lens solutions acting alone. This may provide a benefit in improving the prevention of amoebae eye infections. However, there is still a need for further studies on different pathogenic strains of Acanthamoeba in order to assess the adhesion of the cysts to the contact lens surface and to reveal a more comprehensive picture of the activity of AgTANPs and contact lens solutions.

Advances in the management of Acanthamoeba keratitis: A review of the literature and synthesized algorithmic approach

Acanthamoeba keratitis (AK) is a severe cause of infectious keratitis and represents a significant clinical challenge. Recent literature regarding AK epidemiology, diagnosis, treatment modalities, and prognosis is reviewed and synthesized to propose an algorithmic protocol for AK management. Globally, AK outbreaks in developed countries are ongoing, and AK rates have increased. Moreover, current outbreaks may carry a worse prognosis than prior outbreaks. Despite identification of contact lens solutions implicated in AK outbreaks and the consequent market recall of these products, outbreaks persist. Acanthamoeba keratitis afflicts not only refractive soft contact lens users but also cosmetic contact lens users and gas permeable (especially orthokeratology) lens users. Innovations in in vivo confocal microscopy and PCR assays have increased the role for these adjuvant tests alongside corneal smear and culture in a multimodal diagnostic approach to suspected AK. Biguanides (such as chlorhexidine and polyhexamethylene biguanide) and diamidines (propamidine isethionate and hexamidine) remain cornerstones of AK management, and evidence for other treatment modalities continues to evolve. Voriconazole in topical and systemic forms may be useful as adjuvant therapy. The anti-leishmaniasis drug miltefosine, recently given orphan drug status by the United States Food and Drug Administration, has increasing evidence supporting a role in patients with severe/refractory disease. Prior topical corticosteroids have been consistently shown to be associated with worse outcomes in AK. Although not historically thought of as a treatment modality, benzalkonium chloride preservative may be leveraged for its anti-Acanthamoebal properties. The role of Rose-Bengal photodynamic antimicrobial therapy is evolving in selected cases of AK.