Acanthamoeba keratitis: Molecular typing of Acanthamoeba species directly from ocular tissue.

This report explores the molecular profiling of Acanthamoeba spp. from individuals in the UK suffering from a debilitating, sight-threatening disease of the cornea known as Acanthamoeba keratitis (AK). Seventy ocular samples from individuals undergoing investigations for AK were sent to the Scottish Microbiology Reference Laboratories (SMiRL), Glasgow during 2017-2019, and subjected to DNA extraction followed by in-depth molecular typing using a nested PCR/bi-directional sequencing approach. Of the 70 samples tested, 40 were PCR-positive. Of these, 32 were successfully sequenced and assigned to two of 23 existing genotypes termed T1 to T23. Molecular profiling of the 32 samples highlighted two genotypes, namely T3 (n = 3) and T4 (n = 29). For those 29 samples identified as the T4 genotype, a sub-genotype (T4A-T4H) was recorded: T4A (n = 18); T4B (n = 5); T4C (n = 1); T4E (n = 4); and T4F (n = 1). This study highlights that the T4 genotype and T4A subtype are the predominant molecular variants to cause ocular disease in the UK. Gaining in-depth information on the molecular profiling of Acanthamoeba spp. is essential to increase our understanding of the source(s) of infection, transmission pathways, and potential associations with clinical outcomes for this rare, yet potentially debilitating ocular disease.

A descriptive case of persistent Acanthamoeba keratitis: raising awareness of this complex ocular disease.

BACKGROUND: Acanthamoeba species are ubiquitous free-living organisms found in the environment. They can cause a sight-threatening disease of the cornea termed Acanthamoeba keratitis (AK), often associated with contact-lens wearers. This case review describes a persistent presentation of AK and raises awareness of the challenges faced when diagnosing and managing the disease. It highlights the importance of an accurate and rapid diagnosis to assist patient management and to maximize the potential for a better outcome. CASE PRESENTATION: A 73-year-old female was admitted to hospital due to vision impairment of her left eye. Following a clinical examination, the diagnosis of herpes simplex keratitis (HSK) was reported and treated with antivirals. However, deterioration of her keratitis continued after initial treatment, which prompted an investigation into the possibility of AK. Molecular testing of sequential corneal tissue was performed using a real-time PCR assay alongside further clinical examinations. Acanthamoeba species DNA was isolated from seven out of eight corneal tissues over a 12 month period. Following prolonged drug treatment and two corneal transplants, the individual's symptoms ceased and further molecular testing of corneal tissue was negative. CONCLUSIONS: Acanthamoeba keratitis can be easily misdiagnosed due to the similarities in the clinical presentation to other, much more common ocular pathogens. This case highlights the importance of considering AK in the first-line diagnosis, and raises awareness that an early, accurate and rapid diagnosis is crucial to improve patient outcome.

Endonasal versus external dacryocystorhinostomy for nasolacrimal duct obstruction.

BACKGROUND: A dacryocystorhinostomy (DCR) procedure aims to restore drainage of tears by bypassing a blockage in the nasolacrimal duct, through the creation of a bony ostium that allows communication between the lacrimal sac and the nasal cavity. It can be performed using endonasal or external approaches. The comparative success rates of these two approaches have not yet been established and this review aims to evaluate the relevant up-to-date research. OBJECTIVES: The primary aim of this review is to compare the success rates of endonasal DCR with that of external DCR. The secondary aim is to compare the complication rates between the two procedures. SEARCH METHODS: We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (2016, Issue 8), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to 22 August 2016), Embase (January 1980 to 22 August 2016), Latin American and Caribbean Health Sciences Literature Database (LILACS) (January 1982 to 22 August 2016), Web of Science Conference Proceedings Citation Index- Science (CPCI-S) (January 1990 to 22 August 2016), the ISRCTN registry (www.isrctn.com/editAdvancedSearch), ClinicalTrials.gov (www.clinicaltrials.gov) and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 22 August 2016. We requested or examined relevant conference proceedings for appropriate trials. SELECTION CRITERIA: We included all randomised controlled trials (RCTs) comparing endonasal and external DCRs. DATA COLLECTION AND ANALYSIS: Two review authors independently assessed studies for eligibility and extracted data on reported outcomes. We attempted to contact investigators to clarify the methodological quality of the studies. We graded the certainty of the evidence using GRADE. MAIN RESULTS: We included two trials in this review. One trial from Finland compared laser-assisted endonasal DCR with external DCR, and one trial from India compared mechanical endonasal DCR (using punch forceps) with external DCR. The trials were poorly reported and it was difficult to judge the extent to which bias had been avoided.Anatomic success was defined as the demonstration of a patent lacrimal passage on syringing, or endoscopic visualisation of fluorescein dye at the nasal opening of the anastomoses after a period of at least six months following surgery. Subjective success was defined as the resolution of symptoms of watering following surgery after a period of at least six months. Both included trials used anatomic patency demonstrated by irrigation as a measure of anatomic success. Different effects were seen in these two trials (I2 = 76%). People receiving laser-assisted endonasal DCR were less likely to have a successful operation compared with external DCR (63% versus 91%; risk ratio (RR) 0.69, 95% confidence intervals (CI) 0.52 to 0.92; 64 participants). There was little or no difference in success comparing mechanical endonasal DCR and external DCR (90% in both groups; RR 1.00, CI 0.81 to 1.23; 40 participants). We judged this evidence on success to be very low-certainty, downgrading for risk of bias, imprecision and inconsistency. The trial from Finland also assessed subjective improvement in symptoms following surgery. Resolution of symptoms of watering in outdoor conditions was reported by 84% of the participants in the external DCR group and 59% of those in the laser-assisted endonasal DCR group (RR 0.70, CI 0.51 to 0.97; 64 participants, low-certainty evidence).There were no cases of intraoperative bleeding in any participant in the trial that compared laser-assisted endonasal DCR to external DCR. This was in contrast to the trial comparing mechanical endonasal DCR to external DCR in which 45% of participants in both groups experienced intraoperative bleeding (RR 1.00, 95% CI 0.50 to 1.98; 40 participants). We judged this evidence on intraoperative bleeding to be very low-certainty, downgrading for risk of bias, imprecision and inconsistency.There were only two cases of postoperative bleeding, both in the external DCR group (RR 0.33, 95% CI 0.04 to 3.10; participants = 104; studies = 2). There were only two cases of wound infection/gaping, again both in the external DCR group (RR 0.20, CI 0.01 to 3.92; participants = 40; studies = 1). We judged this evidence on complications to be very low-certainty, downgrading one level for risk of bias and two levels for imprecision due to the very low number of cases. AUTHORS' CONCLUSIONS: There is uncertainty as to the relative effects of endonasal and external DCR. Differences in effect seen in the two trials included in this review may be due to variations in the endonasal technique, but may also be due to other differences between the trials. Future larger RCTs are required to further assess the success and complication rates of endonasal and external DCR. Different techniques of endonasal DCR should also be assessed, as the choice of endonasal technique can influence the outcome. Strict outcome criteria should be adopted to assess functional and anatomical outcomes with a minimal follow-up of six months.

Diagnostic criteria for limbal stem cell deficiency-a systematic literature review.

The diagnosis of limbal stem cell deficiency (LSCD) is often based on clinical manifestations with or without the use of tests to demonstrate the presence of goblet cells or of specific epithelial markers on the corneolimbal surface. This systematic review looks at the various diagnostic methods used in the diagnosis of LSCD in published interventional studies. The design is a systematic literature review. We did a systematic search on MEDLINE and PUBMED for articles published in English between January 1, 2003, and December 31, 2013. We collected data on diagnostic methods used to diagnose LSCD (clinical findings, impression cytology, immunohistochemistry for various epithelial markers, or in vivo confocal microscopy). Forty-six studies (mostly retrospective/interventional case series) met the inclusion criteria. All of the studies used clinical features as evidence of LSCD: discomfort, impaired vision, irregular epithelium, unstable tear film, persistent epithelial defects, scarring, fibrovascular pannus, neovascularization, keratinization, calcification, and opacification of the cornea. Eighteen studies (39.1%) used an additional test for the diagnosis; 17 studies (37.0%) used impression cytology for goblet cells, 4 studies (8.7%) used immunohistochemistry for epithelial markers, and 2 studies (4.3%) use in vivo confocal microscopy. The diagnosis of LSCD was made in most cases on clinical grounds alone. In some studies, diagnostic tests were used, but these varied considerably from study to study. Comparison of effectiveness of various interventions requires standardized diagnostic methods. Consensus on the diagnostic criteria for LSCD is essential and needs to be reached by the interested care providers.

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

Acanthamoeba species are responsible for causing the potentially sight-threatening condition, Acanthamoeba keratitis, which is commonly associated with contact lens use. In this report, we highlight the challenges faced using conventional laboratory identification methods to identify this often under-reported pathogen, and discuss the reasons for introducing the first national service in Scotland for the rapid and sensitive molecular identification of Acanthamoeba species. By comparing culture and molecular testing data from a total of 63 patients (n = 80 samples) throughout Scotland presenting with ocular eye disease, we describe the improvement in detection rates where an additional four positive cases were identified using a molecular assay versus culture. The testing of a further ten patients by confocal imaging is also presented. This report emphasizes the importance of continuing to improve clinical laboratory services to ensure a prompt, correct diagnosis and better prognosis, in addition to raising awareness of this potentially debilitating opportunistic pathogen.

Quantifying changes in corneal neovascularization using fluorescein and indocyanine green angiography.

PURPOSE: To quantify changes in corneal neovascularization in patients with active keratitis after treatment using color imaging, fluorescein angiography (FA), and indocyanine green angiography (ICGA). DESIGN: Prospective, interventional case series. METHODS: Twelve consecutive patients were studied. A comparison of corneal neovascularization parameters was undertaken before and after resolution of the keratitis. A slit-lamp digital camera acquired images of the neovascularization using color imaging, FA, and ICGA. The best-quality images were selected using a grading system, and the neovascular regions of interest were analyzed using automated in-house software. The parameters of analysis were vessel area, diameter, tortuosity, and FA dye leakage. RESULTS: There was a significant reduction in the area of neovascularization after treatment on color imaging (0.78 mm(2); P < .05), FA (2.33 mm(2); P < .01), and ICGA (2.07 mm(2); P < .01). There was also a significant reduction in mean vessel diameter across the region of interest for each patient, more marked on FA (42.74 to 32.52 µm; P < .01) and ICGA (44.77 to 33.29 µm; P < .01) than on color imaging (29.10 to 25.17 µm; P < .01). A significant change in vessel tortuosity was not observed. There was a significant increase in FA dye leakage time (12.41 seconds; P < .05) after treatment. CONCLUSIONS: We demonstrate application of an objective method for analyzing changes in corneal neovascularization. The excellent vessel delineation with ICGA even in the presence of stromal scars makes it an ideal agent for measurement of vessel parameters. FA is useful at detecting vessel leakage, and the time to leakage provides a possible measure of vessel staging.

Imaging and evaluation of corneal vascularization using fluorescein and indocyanine green angiography.

PURPOSE: To evaluate indocyanine green angiography (ICGA) and fluorescein angiography (FA) in imaging and quantifying corneal neovascularization (CNV). METHODS: Patients with CNV were studied using a standardized protocol of color digital photography, FA, and ICGA. Images were graded independently by two observers and assessed for quality, phases of fluorescence, and leakage. Areas of CNV and vasculature geometric properties were analyzed and quantified by an automated program. RESULTS: Twenty-three patients with good quality images were included. Mean times to appearance of ICG and fluorescein were 17 and 20 seconds (P = 0.10). Best images for analysis were obtained at 64 seconds for ICGA and 47 seconds for FA. CNV not apparent on color or FA, particularly in the presence of scarring, was well delineated by ICGA. Leakage of ICGA did not occur. Fluorescein leakage from apical CNV images occurred significantly earlier (32 seconds) in patients with CNV of <6-month duration than those of >1-year (50 seconds) duration (P = 0.04). Mean area of CNV and vessel diameter were similar with ICGA (8.79 mm(2), 0.058 mm) or FA (7.74 mm(2), 0.054 mm) but significantly larger than on color (1.94 mm(2), 0.026 mm) images (P < 0.01). Vessel tortuosity was similar on ICGA (1.16), FA (1.17), and color (1.15) (P = 0.27). CONCLUSIONS: Combined use of FA and ICGA are valuable tools with which to assess CNV and provide better vessel delineation than can be obtained with only color images. Parameters used to assess CNV, such as leakage, area, diameter, and tortuosity, may be useful measures for evaluating treatment. Videography is useful for detecting early leakage.

Glaucoma blind registration in Fife (2000-2009) - a retrospective cohort study.

PURPOSE: To collate information on patients registered blind secondary to glaucoma between 2000 and 2009 and compare findings to an identical study completed a decade earlier between 1990 and 1999. METHODS: The records of all people registered as blind via the Fife Society for the Blind between 2000 and 2009 were retrospectively examined and those with glaucoma as the primary cause were studied in detail. We compared these results with the results of our previous study, in which we examined the same documents for the preceding decade, 1990-1999. RESULTS: The glaucoma blind registration rate was reduced by 31% in the current study compared to the previous one (60 vs 87 patients, p = 0.013). At the same time, there was a 6% increase in blindness registrations due to all causes (881 vs 938, p = 0.62). Patients were referred with significantly fewer visual symptoms (33% vs 60%, p = 0.002) and glaucoma surgery rates increased from 44% to 62% in the current study (p = 0.013). In the later decade, more patients were offered partial sight registration before blind registration (37% vs 10%, p < 0.0001) and sustained independent living at the time of blind registration in this study (66% vs 33%, p < 0.0001). Nearly one-third of patients in the study group had cognitive impairment and/or hearing loss and this was similar to the first study. CONCLUSIONS: The study demonstrates a downward trend in the rates of blind registration due to glaucoma, compared to stable rates of registration for all diseases. Over the time period of the two studies there were refinements in the way glaucoma is managed medically by the hospital eye service and in the community, with a high level of input maintained from the local low vision service.

Endonasal versus external dacryocystorhinostomy for nasolacrimal duct obstruction.

BACKGROUND: Dacryocystorhinostomy (DCR) procedures can be performed using external or endonasal approaches. The comparative success rates of these procedures are unknown. OBJECTIVES: To compare the success rates of external and endonasal approaches to DCR. SEARCH STRATEGY: We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2010, Issue 11), MEDLINE (January 1950 to December 2010), EMBASE (January 1980 to December 2010), Latin American and Caribbean Literature on Health Sciences (LILACS) (January 1982 to December 2010), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com) (December 2010), ClinicalTrials.gov (www.clinicaltrials.gov) (December 2010) and Web of Science Conference Proceedings Citation Index- Science (CPCI-S) (January 1990 to December 2010). There were no language or date restrictions in the search for trials. The electronic databases were last searched on 7 December 2010. We requested or examined relevant conference proceedings for appropriate trials. SELECTION CRITERIA: We included all randomised controlled trials (RCTs) comparing external and endonasal dacryocystorhinostomies. DATA COLLECTION AND ANALYSIS: Two review authors independently performed data extraction and assessment of quality with a predefined form. We contacted investigators to clarify the methodological quality of the studies. MAIN RESULTS: We identified one trial that fulfilled the inclusion criteria. This trial compared 64 DCR procedures (32 external and 32 endonasal procedures). Endonasal DCR was four times more likely to fail compared to external DCR. This was statistically significant (95% confidence interval (CI) 1.25 to 12.84). AUTHORS' CONCLUSIONS: The only trial included in the review provides evidence that endonasal DCR has statistically higher risk of failure compared to external DCR. However, this conclusion is limited by paucity of RCTs, small number of participants and lack of clarity of the methodological process. Well conducted RCTs with sufficient power are required to answer the research question.

Intracameral vancomycin following cataract surgery: An eleven-year study.

AIM: To compare the incidences of endophthalmitis after cataract operations before and after introduction of intracameral vancomycin at the end of surgery. METHODS: A retrospective analysis was performed of presumed infectious endophthalmitis after cataract surgery from January 1, 1998 to December 31, 2008. From January 2001, the practice of using intracameral vancomycin at the end of cataract surgery was introduced. The period before introduction of intracameral vancomycin is considered as period A and that after as period B. The incidences of presumed or culture-proven endophthalmitis during periods A and B were compared. RESULTS: A total of 16,606 cataract surgeries were performed during the study period. The incidence of endophthalmitis per 1000 cataract surgeries was 3.0 during period A and 0.08 during period B. This reduction was statistically significantly (Chi-squared test 36.6, P value < 0.0001). The relative risk of developing endophthalmitis without intracameral vancomycin prophylaxis was 38. The absolute risk reduction was 292 cases of endophthalmitis per 100,000 cataract surgeries. CONCLUSIONS: Intracameral vancomycin significantly reduced the incidence of postoperative endophthalmitis after cataract surgery. There is a universal need to adopt this mode of microbial prophylaxis to reduce the burden of endophthalmitis after cataract surgery.