Infectious Keratitis in Patients Over 65: A Review on Treatment and Preserving Eyesight.

Infectious keratitis (IK) represents a significant global health concern, ranking as the fifth leading cause of blindness worldwide despite being largely preventable and treatable. Elderly populations are particularly susceptible due to age-related changes in immune response and corneal structure. However, research on IK in this demographic remains scarce. Age-related alterations such as increased permeability and reduced endothelial cell density further compound susceptibility to infection and hinder healing mechanisms. Additionally, inflammaging, characterized by chronic inflammation that develops with advanced age, disrupts the ocular immune balance, potentially exacerbating IK and other age-related eye diseases. Understanding these mechanisms is paramount for enhancing IK management, especially in elderly patients. This review comprehensively assesses risk factors, clinical characteristics, and management strategies for bacterial, viral, fungal, and acanthamoeba keratitis in the elderly population, offering crucial insights for effective intervention.

Acanthamoeba keratitis - A review.

This is a comprehensive review after a thorough literature search in PubMed-indexed journals, incorporating current information on the pathophysiology, clinical features, diagnosis, medical and surgical therapy, as well as outcomes of Acanthamoeba keratitis (AK). AK is a significant cause of ocular morbidity, and early diagnosis with timely institution of appropriate therapy is the key to obtaining good outcomes. The varied presentations result in frequent misdiagnosis, and co-infections can increase the morbidity of the disease. The first line of therapy continues to be biguanides and diamidines, with surgery as a last resort.

Clinical outcomes and prognostic factors in Acanthamoeba keratitis.

PURPOSE: To report clinical findings and prognostic factors for visual and morphological outcomes in patients with Acanthamoeba keratitis (AK). METHODS: Single-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. RESULTS: A 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. CONCLUSIONS: In 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.

Impact of implementation of polymerase chain reaction on diagnosis, treatment, and clinical course of Acanthamoeba keratitis.

PURPOSE: Acanthamoeba keratitis (AK) is a painful and possibly sight-threatening ocular infection. While the correct diagnosis and specific treatment in the early stages significantly improve the prognosis, the disease is often misdiagnosed and in clinical examination confused with other forms of keratitis. Polymerase chain reaction (PCR) for the detection of AK was first introduced in our institution in December 2013 to improve the timely diagnosis of AK. The aim of this study was to assess the impact of implementation of Acanthamoeba PCR on the diagnosis and treatment of the disease in a German tertiary referral center. PATIENTS AND METHODS: Patients treated for Acanthamoeba keratitis between 1st of January 1993 and 31st of December 2021 in the Department of Ophthalmology of the University Hospital Duesseldorf were identified retrospectively via in-house registries. Evaluated parameters include age, sex, initial diagnosis, method of correct diagnosis, duration of symptoms until correct diagnosis, contact lens use, visual acuity, and clinical findings as well as medical and surgical therapy by keratoplasty (pKP). In order to assess the impact of implementation of Acanthamoeba PCR, the cases were divided into two groups (before (pre-PCR group) and after PCR implementation (PCR group). RESULTS: Seventy-five patients with Acanthamoeba keratitis were included (69.3% female, median age 37 years). Eighty-four percent (63/75) of all patients were contact lens wearers. Until PCR was available, 58 patients with Acanthamoeba keratitis were diagnosed either clinically (n = 28), by histology (n = 21), culture (n = 6), or confocal microscopy (n = 2) with a median duration until diagnosis of 68 (18; 109) days. After PCR implementation, in 17 patients, the diagnosis was established with PCR in 94% (n = 16) and median duration until diagnosis was significantly shorter with 15 (10; 30.5) days. A longer duration until correct diagnosis correlated with a worse initial visual acuity (p = 0.0019, r = 0.363). The number of pKP performed was significantly lower in the PCR group (5/17; 29.4%) than in the pre-PCR group (35/58; 60.3%) (p = 0.025). CONCLUSIONS: The choice of diagnostic method and especially the application of PCR have a significant impact on the time to diagnosis and on the clinical findings at the time of confirmation of diagnosis and the need for penetrating keratoplasty. In contact lens-associated keratitis, the first crucial step is to take AK into consideration and perform a PCR test as timely confirmation of diagnosis of AK is imperative to prevent long-term ocular morbidity.

Management of refractory Acanthamoeba keratitis, two cases.

Acanthamoeba keratitis is a serious infection of the eye that can result in permanent visual impairment or blindness, caused by free-living amoebae of the genus Acanthamoeba. Early diagnosis is necessary for effective treatment of Acanthamoeba keratitis. Acanthamoeba is abundant in nature and can be found in water, soil, and air. Acanthamoeba keratitis is usually diagnosed by culture from a scraping of the eye or by confocal microscopy. In this paper, two complicated Acanthamoeba keratitis cases are reported.

[Coinfections in contact lens-associated mycotic keratitis with Pseudomonas or Acanthamoeba]. / Mischinfektionen bei kontaktlinsenassoziierter mykotischer Keratitis mit Pseudomonas oder Akanthamöben.

Contact lens-associated keratitis is becoming increasingly more frequent. Fungal keratitis is a relatively rare clinical picture but must be taken very seriously. Especially in the early stages of the disease, it may be clinically misdiagnosed and adequate treatment is therefore delayed. In treatment-resistant contact lens-associated fungal keratitis, coinfections or superinfections can occur. We present two patients with an initially unclear keratitis, in whom a fungal keratitis with coinfection of Pseudomonas aeruginosa and Acanthamoeba, respectively, could be confirmed. In both cases an urgent excimer laser penetrating keratoplasty with interrupted sutures and adequate local topical treatment for 8 weeks was successful.

Acanthamoeba keratitis: A 4-year review from a tertiary care hospital in North India.

INTRODUCTION: Acanthamoeba keratitis (AK) is a blinding condition reported from both developed and developing countries. Limited knowledge on the clinical characteristics of AK and scarce laboratory diagnostic facilities in such countries poses difficulties in the accurate diagnosis. OBJECTIVE: To describe the epidemiological and clinical characteristics as well as management of Acanthamoeba keratitis in a tertiary care hospital in North India. METHODS: All clinically suspicious cases of Acanthamoeba keratitis (AK) presenting to our centre were screened for Acanthamoeba. All patients diagnosed as Acanthamoeba on microscopic examination, culture and polymerase chain reaction (PCR) were given Polyhexamethylene biguanide (PHMB) eye drops 0.02% half hourly for 1 week, then hourly for 1 week and then gradually tapered according to the response. Out of 300 consecutive patients evaluated, Acanthamoeba was detected in 11(3.6%) patients. A history of trauma was elicited in majority of the patients, 6 (55%). The most common complaints were eye pain, redness and watering in all of the patients, diminution of vision (8, 72.7%), photophobia (7, 63.6%) and foreign body sensation (2, 18.2%). Complete healing with vascularization and scarring was observed in 7 patients (63.6%) patients whereas progression to perforation of corneal ulcer and corneal melt was seen in 3 (27.3%) cases and these patients underwent therapeutic keratoplasty later. One patient did not come for follow up examination. CONCLUSION: The most common risk factor for the occurrence of Acanthamoeba Keratitis is trauma followed by contact lens use.

Use of Vivostat PRF® in Acanthamoeba keratitis.

We present a case of a 27-year-old contact lens male user who was diagnosed with Acanthamoeba keratitis. Given the inefficiency of medical treatment and high risk of corneal perforation, we decided to use Vivostat PRF®, with satisfactory results. To our knowledge, this is the first described case in medical literature in which Vivostat PRF® is used as part of Acanthamoeba keratitis treatment.

Acanthamoeba keratitis in Australia: demographics, associated factors, presentation and outcomes: a 15-year case review.

PURPOSE: To report the demographics, frequency of potential predisposing factors, presentation and outcomes of Acanthamoeba keratitis (AK) at a quaternary eye hospital in Sydney, Australia over a 15-year period. METHODS: A retrospective review of all patients diagnosed with AK at the Sydney Eye Hospital, Sydney, Australia between January 2002 and December 2016 was conducted. RESULTS: A total of 52 patients with AK at the quaternary referral hospital in Sydney, Australia, between January 2002 and December 2016, were included. The most commonly documented potential predisposing factors were contact lens wear (83%) and organic trauma (10%) in the non-contact lens wearers. An initial misdiagnosis of herpetic eye disease was made in 37% of patients. The presenting clinical features in order of frequency included; punctate epitheliopathy in 65% (n = 34), perineural infiltrate 46% (n = 24), stromal infiltrates 46% (n = 24), anterior uveitis 39% (n = 20), epithelial defect 35% (n = 18), limbitis 31% (n = 16), pseudo-dendrite 19% (n = 10), and ring infiltrate 4% (n = 7). Twenty-seven of the patients completed their follow-up at the Sydney Eye Hospital, improving their vision from 1.02 logMAR at presentation to 0.57 logMAR at last follow-up. Thirty-nine complications developed in 32 eyes and included corneal scarring and vascularisation, three patients experienced recurrences of AK and one patient developed a late-onset scleritis. CONCLUSION: In Australia, AK occurred predominantly in contact lens wearers with typical clinical features including epitheliopathy and perineural infiltrates. The patient demographics, frequency of potential predisposing factors and clinical presentation of AK were similar to case series from the UK and New Zealand.

Early therapeutic lamellar keratoplasty for acanthamoeba keratitis followed by implantable Collamer lens for visual rehabilitation.

We are reporting the case of a 25-year-old female who developed acanthamoeba keratitis after wearing contact lenses for high myopia. She was diagnosed as acanthamoeba and started the treatment of antiacanthamoeba for 3 consecutive weeks, followed by bare Descemet's therapeutic lamellar keratoplasty (LKP) with the maintenance of antiacanthamoeba treatment to control the infection. In the late postoperative period, visual rehabilitation was obtained by insertion of implantable Collamer lens (ICL) with her final visual outcome was 20/30. For acanthamoeba keratitis, early bare Descemet's therapeutic LKP has a better outcome in comparison to late penetrating keratoplasty in terms of infection eradication and globe preservation. After removal of all sutures, the refractive error can be corrected with photorefractive procedures as well as ICL.

Acanthamoeba keratitis related to contact lens use in a tertiary hospital in China.

BACKGROUND: To report the clinical and microbiological features of Acanthamoeba keratitis (AK) related to contact lens use in a tertiary hospital in China. METHODS: In this retrospective study, the medical results of 61 cases of AK related to contact lens use from January 2000 to December 2017 were reviewed. The data included patients' demographics, lens type, history, risk factors, disease stages, corneal scraping and culture reports, and treatments. Moreover, genotypic identification of some of the isolates was carried out with a PCR assay and sequence analysis of the 18S ribosomal DNA gene. RESULTS: There were 64 eyes included in the study. A total of 32.8% of the patients wore soft contact lenses, and 67.2% of patients used overnight orthokeratology. In the cases (20 eyes) in the early stage, 65% (13 eyes) had positive results according to Giemsa-stained smears, and 0.9% sodium chloride (NaCl) wet mounts revealed trophozoites in 7 eyes (35%). Six eyes (30%) were diagnosed by confocal microscopy combined with clinical signs. In the orthokeratology patients, 87.8% (36/41) rinsed their lenses and/or cases with tap water; 55% of soft-lens wearers wore their lenses while showering. The genotype of 9 isolates was determined, and all the strains belonged to genotype T4. In the orthokeratology group, the number of patients who required therapeutic penetrating keratoplasty after 2005 was less than that before 2005 (chi-square test, χ2 = 4.209, P = 0.04). CONCLUSIONS: More than two-thirds of the cases were associated with orthokeratology. Examinations with Giemsa-stained smears, 0.9% NaCl wet mounts and confocal microscopy should be performed for patients who are highly suspected of having early-stage AK to help with early diagnosis. In the orthokeratology group, the rate of therapeutic keratoplasty after 2005 was less than that before 2005.

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.

Early Penetrating Keratoplasty À Chaud May Improve Outcome in Therapy-Resistant Acanthamoeba Keratitis.

INTRODUCTION: Long-standing acanthamoeba keratitis (AK) may result in corneal neovascularization, extension of the infiltrate to the limbus or sclera, broad peripheral synechiae, mature cataract or ischemic posterior segment inflammation. We investigated the impact of early emergency penetrating keratoplasty (PKP) in therapy-resistant cases among the patients of a highly specialized tertiary care center. METHODS: In this retrospective, observational cohort within a single institution, we collected data on best-corrected visual acuity (BCVA), epithelial wound healing, graft survival and secondary complications of AK patients who underwent PKP. A total of 23 eyes of 23 patients diagnosed with acute, therapy-resistant AK between 2006 and 2015 were enrolled. Postoperative combined topical treatment was tapered for 6-9 months. RESULTS: Eyes were grouped based on preoperative disease duration as shorter (group 1) or longer (group 2) than the median. The median was 5.3 (0.66-36) months. The BCVA in group 1 (20/44 ± 20/18; 0.32 ± 0.18 logMAR) was significantly better than in group 2 (20/1200 ± 20/1133; 1.28 ± 0.89; logMAR); p = 0.015. Persisting epithelial defects occurred in 5 patients (50%) of group 1 and in 10 patients (77%) of group 2. In 5 eyes (group 2), no epithelial healing could be achieved. After 36 months, graft survival (Kaplan-Meier) was 78% (18 grafts) for all patients (90% in group 1 and 44% in group 2). CONCLUSION: PKP à chaud within 5.3 months after first symptoms of therapy-resistant AK seems to result in better final BCVA than delayed graft surgery if the disease is resistant to a classical topical triple therapy. In addition, early PKP may have a favorable impact on epithelial healing and graft survival. FUNDING: We thank the Alexander von Humboldt Foundation for supporting the work of Prof. N. Szentmáry at the Department of Ophthalmology of Saarland University Medical Center in Homburg/Saar, Germany. We thank the University of Saarland for funding the medical writing assistance and the Rapid Service Fees. The funding organisation had no role in the design or conduct of this research.

Clinical course of Acanthamoeba keratitis by genotypes T4 and T8 in Hungary.

Genus Acanthamoeba is an opportunistic protozoan that is widely distributed in the environment. Within this genus, numerous species are recognized as human pathogens, potentially causing Acanthamoeba keratitis (AK). AK is a corneal disease, associated predominantly with contact lens (CL) wear; its epidemiology is related to the specific Acanthamoeba genotypes. This study reports seven CL wearer, Acanthamoeba PCR-positive patients with AK, diagnosed between January 2015 and 2018. Patients had the diagnosis of AK 1.36 months after first symptoms. Genotyping allowed the identification of six isolates of the T4 and one of the T8 genotypes. At first presentation, pseudendritiformic epithelopathy/dirty epithelium (four eyes, 57.1%), multifocal stromal infiltrates (five eyes, 71.4%), ring infiltrate (three eyes, 42.8%), and perineuritis (one eye, 14.3%) were observed. AK was healed without later recurrence in two eyes (28.5%) using triple-topical therapy, in three eyes (42.8%) following additional penetrating keratoplasty. In one patient (14.3%), AK recurred following successful application of triple-therapy and was treated successfully with repeated triple-topical therapy and in one patient (14.3%), no follow-up data were available after diagnosis. We could not observe correlation of genotype and clinical course or the necessity of corneal transplantation in our case series.

Accelerated collagen cross-linking in the management of advanced Acanthamoeba keratitis / Cross-linking acelerado de colágeno no controle da ceratite por Acanthamoeba avançada

ABSTRACT Purpose: To report our initial experience in the treatment of Acanthamoeba keratitis with accelerated corneal collagen cross-linking. Methods: Retrospective chart review of patients diagnosed with Acanthamoeba keratitis with progressive corneal melting who were treated with accelerated collagen cross-linking. Results: A total of 6 eyes (5 patients) were reviewed. All the patients received adjuvant therapy with moxifloxacin and chlorhexidine. In 4 cases, the ulcer healed with a mean interval to epithelialization of 108.8 days (range 59-217). In 2 eyes, there was a persistent neurotrophic ulcer. The melting was not progressive in any case, nor did any eye required emergency penetrating keratoplasy. Conclusion: This study suggests a beneficial effect of accelerated collagen cross-linking in cases of Acanthamoeba keratitis with corneal melting. Thus, collagen cross-linking may be considered as adjuvant treatment for Acanthamoeba keratitis.

RESUMO Objetivo: Relatar nossa experiência inicial no tra tamento da ceratite por Acanthamoeba com reticulação acelerada de colágeno corneano. Métodos: Revisão retrospectiva de prontuários de pacientes diagnosticados com ceratite por Acanthamoeba, com deformação progressiva da córnea, tratados com reticulação acelerada de colágeno. Resultados: Seis olhos (5 pacientes) foram incluídos. Todos os pacientes receberam terapia adjuvante com moxifloxacina e clorexidina. Em 4 casos, a úlcera cicatrizou com uma média de epitelização de 108,8 dias (amplitude de 59-217 dias). Em dois pacientes, a úlcera apresentou um comportamento neurotrófico. A deformação não foi progressiva em nenhum dos pacientes e nenhum dos olhos exigiu ceratoplastia penetrante de emergência. Conclusão: Este estudo sugeriu um efeito benéfico da reticulação acelerada de colágeno em casos de ceratite por Acanthamoeba infecciosa com deformação corneal. A reticulação de colágeno parece ser uma alternativa coadjuvante possível para casos de ceratite por Acanthamoeba.

Accelerated collagen cross-linking in the management of advanced Acanthamoeba keratitis.

PURPOSE: To report our initial experience in the treatment of Acanthamoeba keratitis with accelerated corneal collagen cross-linking. METHODS: Retrospective chart review of patients diagnosed with Acanthamoeba keratitis with progressive corneal melting who were treated with accelerated collagen cross-linking. RESULTS: A total of 6 eyes (5 patients) were reviewed. All the patients received adjuvant therapy with moxifloxacin and chlorhexidine. In 4 cases, the ulcer healed with a mean interval to epithelialization of 108.8 days (range 59-217). In 2 eyes, there was a persistent neurotrophic ulcer. The melting was not progressive in any case, nor did any eye required emergency penetrating keratoplasy. CONCLUSION: This study suggests a beneficial effect of accelerated collagen cross-linking in cases of Acanthamoeba keratitis with corneal melting. Thus, collagen cross-linking may be considered as adjuvant treatment for Acanthamoeba keratitis.

Box Behnken design of siRNA-loaded liposomes for the treatment of a murine model of ocular keratitis caused by Acanthamoeba.

Acanthamoeba keratitis is an ophthalmic disease with no specific treatment that specially affects contact lens users. The silencing of serine phosphatase (SP) and glycogen phosphorylase (GP) proteins produced by Acanthamoeba has been shown to significantly reduce the cytopathic effect, although no vehicle was proposed yet to deliver the siRNA sequences to the trophozoites. In this study, PEGylated cationic liposomes were proposed and optimized using Box-Behnken design. The influence of DOTAP:DOPE ratio, DSPE-PEG concentration, and siRNA/DOTAP charge ratio were evaluated over both biological response and physicochemical properties of liposomes. The ratio of DOTAP:DOPE had an effect in the trophozoite activity whereas the charge ratio influenced both size and protease activity. The predicted values were very close to the observed values, yielding a formulation with good activity and toxicity profile, which was used in the following experiments. A murine model of ocular keratitis was treated with siGP + siSP-loaded liposomes, as well as their respective controls, and combined treatment of liposomes and chlorhexidine. After 15 days of eight daily administrations, the liposomal complex combined with chlorhexidine was the only treatment able to reverse the more severe lesions associated with keratitis. There was 60% complete regression in corneal damage, with histological sections demonstrating the presence of an integral epithelium, without lymphocytic infiltrate. The set of results demonstrate the efficacy of a combined therapy based on siRNA with classical drugs for a better prognosis of keratitis caused by Acanthamoeba.

Case Report: Corneal Coinfection with Fungus and Amoeba: Report of Two Patients and Literature Review.

We report two cases of corneal coinfection with Acanthamoeba and Fusarium sp. along with the review of published literature. A 35-year-old woman and 65-year-old man presented to the institute with corneal ulcer refractory for treatment with topical antibiotics. Microbiological examination revealed the presence of Acanthamoeba cysts along with septate, hyaline fungal filaments. After emergency therapeutic penetrating keratoplasty (TPK) in both, the corneal tissue was sent for histopathologic examination, which confirmed the presence of Acanthamoeba and fungal coinfection. One patient had a recurrence of fungal infection after TPK. In subjects with a rapid progression of mycotic ulcer, coinfection with other microorganisms including Acanthamoeba should be suspected. The two cases presented here emphasize the importance of microbiology in making prompt diagnosis and appropriate management of these cases at an early stage.

A report of 10 patients with Acanthamoeba keratitis. / Casuística de 10 pacientes con queratitis por Acanthamoeba.

CLINICAL CASES: Cases are presented of 10 patients with Acanthamoeba keratitis treated between 2008 and 2017. All were contact lens wearers. All of them received treatment with a biguanide combined with a diamidine. In 3 cases the infestation did not exceed the superficial stroma, responding to topical treatment. In 7, the infection reached the deep stroma, with 6 of these cases requiring penetrating keratoplasty (PKP), 3 of them therapeutic PKP because of perforation risk or ocular spreading. The visual acuity improved in all the cases. CONCLUSION: The infestation depth at the time of diagnosis appears to be the main risk factor for requiring a PKP.