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To describe the clinical profile of patients presented with Acanthamoeba keratitis (AK) to a multi-tier ophthalmology hospital network in India. This cross-sectional hospital-based study included 1945339 new patients registering between September 2016 and May 2022. Patients with clinically confirmed diagnosis of AK in one or both eyes were included in the study. All the relevant data were documented using an electronic medical record (EMR) system. A total of 245 (0.013%) patients were diagnosed with AK and majority were male (62.86%) with unilateral (99.59%) affliction. The most common age group was during the fourth decade of life, 65 (26.53%) patients and predominantly were adults (95.51%). The prevalence of the infection was higher in patients from a lower socioeconomic status (43.27%) from rural geography (52.24%) and in agriculture-related work (28.16%). The most common inciting factor was injury with vegetative matter (8.98%), dust (7.76%) and contact lens wear (4.49%). The majority of the eyes had blindness (20/400 to 20/1200) in 116 (47.15%) eyes with a presenting visual acuity (logMAR) of 2.14 ± 1.04. Among the surgical interventions, therapeutic keratoplasty was performed in 41 (16.67%) eyes, penetrating keratoplasty in 22 (8.94%) eyes, and evisceration in 2 (0.81%) eyes. AK more commonly affects males presenting during the fourth decade of life from lower socio-economic status and is predominantly unilateral. A fourth of the affected eyes underwent keratoplasty and the majority had significant visual impairment at presentation. [ABSTRACT FROM AUTHOR]

The free-living amebae of genus Acanthamoeba are an important cause of microbial keratitis. The clinical appearance of Acanthamoeba keratitis (AK) usually mimics viral or fungal keratitis. Thus, microbiological workup plays a significant role in the diagnosis and timely treatment of such cases. We report a retrospective case series of seven culture-confirmed AK cases from a tertiary eye care center in North India. Various risk factors and triggers of infection, clinical presentations, microbiological findings, and management of AK are elucidated. [ABSTRACT FROM AUTHOR]

Background: Acanthamoeba keratitis is challenging to treat and thought to result in poor outcomes, but very few comparative studies exist to assess whether ulcers caused by Acanthamoeba are worse than those caused by bacteria or fungus. Methods: In a retrospective cohort study, all cases of smear- or culture-proven Acanthamoeba keratitis diagnosed from January 2006 to June 2011 at an eye hospital in South India were identified from the microbiology database. Random samples of the same number of cases of bacterial and fungal keratitis, matched by year, were identified from the same database in order to compare outcomes between the three types of organism. The main outcomes were the time until the following events: re-epithelialization, discontinuation of antimicrobials, perforation/keratoplasty, elevated intraocular pressure, and new cataract. Results: The median time until re-epithelialization was 113 days for Acanthamoeba keratitis, 30 days for fungal keratitis, and 25 days for bacterial keratitis, and the median time until discontinuation of antimicrobial therapy was 100 days for Acanthamoeba keratitis, 49 days for fungal keratitis, and 40 days for bacterial keratitis. Compared to the other two organisms, Acanthamoeba ulcers took significantly longer to re-epithelialize (adjusted HR 0.4, 95% CI 0.3 to 0.6 relative to bacterial ulcers and HR 0.3, 95% CI 0.2 to 0.5 relative to fungal ulcers; overall p<0.001) and had significantly longer courses of antimicrobials (adjusted HR 0.3, 95% CI 0.2 to 0.6 relative to bacterial ulcers and HR 0.5, 95%CI 0.3 to 0.8 relative to fungal ulcers; overall p<0.001). No statistically significant difference was observed between the three organisms for the other time-to-event outcomes. Conclusions: Acanthamoeba keratitis was more difficult to treat and had worse clinical outcomes than bacterial or fungal ulcers, highlighting the lack of adequate treatment regimens for this infection. [ABSTRACT FROM AUTHOR]

The purpose of the study is to describe epidemiology, clinical features, diagnosis, and treatment of Acanthamoeba keratitis (AK) with special focus on the disease in nonusers of contact lenses (CLs). This study was a perspective based on authors' experience and review of published literature. AK accounts for 2% of microbiology-proven cases of keratitis. Trauma and exposure to contaminated water are the main predisposing factors for the disease. Association with CLs is seen only in small fraction of cases. Contrary to classical description experience in India suggests that out of proportion pain, ring infiltrate, and radial keratoneuritis are seen in less than a third of cases. Majority of cases present with diffuse infiltrate, mimicking herpes simplex or fungal keratitis. The diagnosis can be confirmed by microscopic examination of corneal scraping material and culture on nonnutrient agar with an overlay of Escherichia coli. Confocal microscopy can help diagnosis in patients with deep infiltrate; however, experience with technique and interpretation of images influences its true value. Primary treatment of the infection is biguanides with or without diamidines. Most patients respond to medical treatment. Corticosteroids play an important role in the management and can be used when indicated after due consideration to established protocols. Surgery is rarely needed in patients where definitive management is initiated within 3 weeks of onset of symptoms. Lamellar keratoplasty has been shown to have good outcome in cases needing surgery. Since the clinical features of AK in nonusers of CL are different, it will be important for ophthalmologists to be aware of the scenario wherein to suspect this infection. Medical treatment is successful if the disease is diagnosed early and management is initiated soon. [ABSTRACT FROM AUTHOR]

Purpose: To determine the epidemiological and clinical characteristics of Acanthamoeba keratitis and also to determine the sensitivity and specificity of smears in the detection of Acanthamoeba.Materials and Methods: A retrospective review of all culture-positive cases of Acanthamoeba keratitis seen between October 1999 and August 2002 was performed. Corneal scrapes were subjected to culture and microscopy using standard protocols.Results: Out of 3183 consecutive patients with clinically diagnosed corneal ulcers evaluated, 33 (1.04%) were found to be due to Acanthamoeba. Twenty-four out of 33 (72.72%) were less than 51 years of age (P<0.001). All patients were from rural areas (P<0.001) and 26 (78.79%) of them were agricultural workers (P=0.031). All 33 had history of corneal injury (P<0.001) and 28 (84.85%) patients had injury with mud (P<0.001). All 33 (100%) patients had previous medical treatment (P=0.009) and 10 (30.3%) had used traditional eye medicines (P=0.183). A clinical pattern of ring infiltrate was characteristic in 15 (45.45%) patients. The diameter of the corneal ulcer was more than 6 mm in 27 (81.82%) eyes (P<0.001). Twenty-six (78.79%) patients had visual acuity of perception of light on initial presentation (P<0.001) and 24 (72.73%) had the same as their final visual outcome. The sensitivity of 10% potassium hydroxide (KOH) preparation was found to be higher (P<0.001) in the detection of Acanthamoeba cysts.Conclusion: The incidence of Acanthamoeba keratitis amongst the corneal ulcer patients was 1% in this setting and it was mainly due to corneal injury by mud. The KOH preparation is a sensitive diagnostic tool for the detection of Acanthamoeba. Delayed diagnosis or misdiagnosis and inappropriate antimicrobial therapy results in poor visual outcome. [ABSTRACT FROM AUTHOR]

• Out of the 300 clinically suspected cases, a final diagnosis of Acanthamoeba keratitis was made in 11 patients, giving a prevalence of 3.6% among non-bacterial non-fungal keratitis patients. • Seven (2.3%) were positive by smear microscopy, 9 (3%) by NNA culture, 11 (3.6%) by cPCR and 11 (3.6%) by qPCR. • Sensitivity of smear microscopy, culture, cPCR and qPCR was 63.6%, 81.8%, 100% and 100%, respectively. • The lowest gDNA concentration at which distinct amplification was obtained was 1 pg/µl for cPCR and 0.1 pg/µl for qPCR. • 18S rDNA sequencing revealed that A. castellanii was the predominant species and isolates were genetically distinct. Acanthamoeba keratitis (AK) is a painful vision-threatening infection caused by pathogenic free-living Acanthamoeba. Due to the non-specific clinical presentation, this condition tends to be misdiagnosed by clinicians. A timely diagnosis is crucial for favorable visual outcome. Three hundred patients with suspected microbial keratitis presenting to the Advanced Eye Center at our tertiary care center in North India during the period from 2014 to 2018 were included. Patient's corneal scrapings, contact lens, lens solution, lens case, and tears were processed for microscopic examination by Giemsa and Calcofluor staining, non-nutrient agar (NNA) culture and molecular diagnosis by conventional PCR (cPCR) and Real-time PCR (qPCR). 18S rDNA gene sequencing was done to assess phylogenetic relationship. AK was found in 3.6% (11/300) of non-bacterial non-fungal keratitis patients. Among microbiological techniques, microscopy for Acanthamoeba was positive in 7 cases, NNA culture was positive in 9 cases and 11 cases were detected both by cPCR and qPCR. The sensitivity of microscopy, culture, cPCR and qPCR was 63.64%, 81.82 %, 100%, and 100% respectively whereas specificity was 100% for all the tests. 18S rDNA sequencing revealed that A. castellanii was the predominant species and isolates were genetically distinct. AK should be considered in the differential diagnosis of infectious keratitis. Molecular tests are useful for rapid, sensitive and specific diagnosis and must be included in workup of keratitis. [ABSTRACT FROM AUTHOR]