When the implementation of water safety plans fail: rethinking the approach to water safety planning following a serious waterborne outbreak and implications for subsequent water sector reforms.

Water suppliers in New Zealand have been preparing the water safety plans (WSPs) since 2005; large drinking water-associated outbreaks of campylobacteriosis occurred in Darfield in 2012 and in Havelock North in 2016. This paper reviews the WSP that was in place for Havelock North, and analyses why it failed to prevent this outbreak. The risk assessment team completing the WSP underestimated the risks to human health of contamination events, while overestimating the security of the groundwater and bore heads. Historical Escherichia coli transgressions were dismissed as likely despite sampler or testing errors, rather than important warning signals. The outbreak was a consequence of multiple factors including an untreated supply, a local animal faecal source, limitations to the aquifer integrity and bore head protection, and a failure to proactively respond to a flooding event. The overarching issue was a focus on narrow compliance with the Health Act rather than the use of the WSP as a valuable tool to proactively understand and manage public health risks. New Zealand plans to focus on the ability of an organisation to manage risk, with the emphasis on promoting conversations with water suppliers about integrated risk management rather than focusing solely on the preparation of a WSP.

Optimizing COPD Acute Care Patient Outcomes Using a Standardized Transition Bundle and Care Coordinator: A Randomized Clinical Trial.

BACKGROUND: Acute exacerbations of COPD (AECOPD) are associated with high morbidity and mortality and frequent readmissions. RESEARCH QUESTION: What is the effectiveness of a COPD transition bundle, with and without a care coordinator, on rehospitalizations and ED revisits? STUDY DESIGN AND METHODS: Two patient cohorts were selected: (1) the group exposed to the transition bundle and (2) the group not exposed to the transition bundle (usual care group). Patients exposed subsequently were randomized to a care coordinator. An AECOPD transition bundle was implemented in the hospital; patients randomized to the care coordinator were contacted ≤ 72 h after discharge. Six hundred four patients (320 to the care coordinator and 284 to routine care) who met eligibility criteria from five hospitals across three cities in Alberta, Canada, were exposed to the transition bundle, whereas 3,106 patients discharged from the same hospitals received the usual care. Primary outcomes were 7-day, 30-day, and 90-day readmissions, median length of stay (LOS), and 30-day ED revisits. RESULTS: The transition bundle cohort were 83% (relative risk [RR], 0.17; 95% CI, 0.07-0.35) less likely to be readmitted within 7 days and 26% (RR, 0.74; 95% CI, 0.60-0.91) less likely to be readmitted within 30 days of discharge. Ninety-day readmissions were unchanged (RR, 1.05; 95% CI, 0.93-1.18). The transition bundle was associated with a 7.3% (RR, 1.07; 95% CI, 1.0-1.15) relative increase in LOS and a 76% (RR, 1.76; 95% CI, 1.53-2.02) greater risk of a 30-day ED revisit. The care coordinator did not influence readmission or ED revisits. INTERPRETATION: The COPD transition bundle reduced 7- and 30-day hospital readmissions while increasing LOS and ED revisits. The care coordinator did not improve outcomes. TRIAL REGISTRY: ClinicalTrials.gov; No.: NCT03358771; URL: www. CLINICALTRIALS: gov.

The ADEPT study: a comparative study of dentists' ability to detect enamel-only proximal caries in bitewing radiographs with and without the use of AssistDent artificial intelligence software.

Introduction Reversal of enamel-only proximal caries by non-invasive treatments is important in preventive dentistry. However, detecting such caries using bitewing radiography is difficult and the subtle patterns are often missed by dental practitioners.Aims To investigate whether the ability of dentists to detect enamel-only proximal caries is enhanced by the use of AssistDent artificial intelligence (AI) software.Materials and methods In the ADEPT (AssistDent Enamel-only Proximal caries assessmenT) study, 23 dentists were randomly divided into a control arm, without AI assistance, and an experimental arm, in which AI assistance provided on-screen prompts indicating potential enamel-only proximal caries. All participants analysed a set of 24 bitewings in which an expert panel had previously identified 65 enamel-only carious lesions and 241 healthy proximal surfaces.Results The control group found 44.3% of the caries, whereas the experimental group found 75.8%. The experimental group incorrectly identified caries in 14.6% of the healthy surfaces compared to 3.7% in the control group. The increase in sensitivity of 71% and decrease in specificity of 11% are statistically significant (p <0.01).Conclusions AssistDent AI software significantly improves dentists' ability to detect enamel-only proximal caries and could be considered as a tool to support preventive dentistry in general practice.

The saprophytic fungus Fusarium solani increases the insecticidal efficacy of the entomopathogenic nematode Steinernema diaprepesi.

In two field surveys, high proportions of Galleria mellonella L. (Lepidoptera: Pyralidae) sentinel larval cadavers were infected by Fusarium solani without evidence of concomitant entomopathogenic nematode (EPN) or entomopathogenic fungus (EPF) reproduction. Because F. solani is not considered entomopathogenic, the survey suggested the possibility that F. solani competes with EPNs. We tested the hypotheses that F. solani attracts the EPN, Steinernema diaprepesi, to facilitate infection of Diaprepes root weevils (Diaprepes abbreviatus L.) and thereafter competes with the nematode in the insect cadaver. In two-choice olfactometer assays where one side was treated with F. solani mycelia and conidia, juvenile S. diaprepesi were attracted to the fungus, in either raw soil, or in autoclaved soil in the presence or absence of insects. However, this attraction was attenuated as the habitat became more complex, by using raw soil in combination with insect larvae. Fusarium oxysporum did not recruit the nematode. When soil microcosms were tested with F. solani conidia and S. diaprepesi, the concomitant infection increased the mortality of the insect (P = 0.02) to 83%, compared to 58% and 0% mortality when nematodes or fungi were individually applied, respectively. Concomitant inoculation also increased the number of cadavers that supported nematode reproduction and increased the population density of fungus in soil. The number of IJs entering the host insect was not affected by F. solani. These results support the possibility that F. solani can facilitate the insecticidal efficiency of S. diaprepesi in order to exploit the resources in the cadaver.

Effectiveness of a standardized electronic admission order set for acute exacerbation of chronic obstructive pulmonary disease.

BACKGROUND: Variation in hospital management of patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD) may prolong length of stay, increasing the risk of hospital-acquired complications and worsening quality of life. We sought to determine whether an evidence-based computerized AECOPD admission order set could improve quality and reduce length of stay. METHODS: The order set was designed by a provincial COPD working group and implemented voluntarily among three physician groups in a Canadian tertiary-care teaching hospital. The primary outcome was length of stay for patients admitted during order set implementation period, compared to the previous 12 months. Secondary outcomes included length of stay of patients admitted with and without order set after implementation, all-cause readmissions, and emergency department visits. RESULTS: There were 556 admissions prior to and 857 admissions after order set implementation, for which the order set was used in 47%. There was no difference in overall length of stay after implementation (median 6.37 days (95% confidence interval 5.94, 6.81) pre-implementation vs. 6.02 days (95% confidence interval 5.59, 6.46) post-implementation, p = 0.26). In the post-implementation period, order set use was associated with a 1.15-day reduction in length of stay (95% confidence interval - 0.5, - 1.81, p = 0.001) compared to patients admitted without the order set. There was no difference in readmissions. CONCLUSIONS: Use of a computerized guidelines-based admission order set for COPD exacerbations reduced hospital length of stay without increasing readmissions. Interventions to increase order set use could lead to greater improvements in length of stay and quality of care.

Corneal Nerve Fractal Dimension: A Novel Corneal Nerve Metric for the Diagnosis of Diabetic Sensorimotor Polyneuropathy.

Objective: Corneal confocal microscopy (CCM), an in vivo ophthalmic imaging modality, is a noninvasive and objective imaging biomarker for identifying small nerve fiber damage. We have evaluated the diagnostic performance of previously established CCM parameters to a novel automated measure of corneal nerve complexity called the corneal nerve fiber fractal dimension (ACNFrD). Methods: A total of 176 subjects (84 controls and 92 patients with type 1 diabetes) with and without diabetic sensorimotor polyneuropathy (DSPN) underwent CCM. Fractal dimension analysis was performed on CCM images using purpose-built corneal nerve analysis software, and compared with previously established manual and automated corneal nerve fiber measurements. Results: Manual and automated subbasal corneal nerve fiber density (CNFD) (P < 0.0001), length (CNFL) (P < 0.0001), branch density (CNBD) (P < 0.05), and ACNFrD (P < 0.0001) were significantly reduced in patients with DSPN compared to patients without DSPN. The areas under the receiver operating characteristic curves for identifying DSPN were comparable: 0.77 for automated CNFD, 0.74 for automated CNFL, 0.69 for automated CNBD, and 0.74 for automated ACNFrD. Conclusions: ACNFrD shows comparable diagnostic efficiency to identify diabetic patients with and without DSPN.

An Automatic Tool for Quantification of Nerve Fibers in Corneal Confocal Microscopy Images.

OBJECTIVE: We describe and evaluate an automated software tool for nerve-fiber detection and quantification in corneal confocal microscopy (CCM) images, combining sensitive nerve- fiber detection with morphological descriptors. METHOD: We have evaluated the tool for quantification of Diabetic Sensorimotor Polyneuropathy (DSPN) using both new and previously published morphological features. The evaluation used 888 images from 176 subjects (84 controls and 92 patients with type 1 diabetes). The patient group was further subdivided into those with ( n = 63) and without ( n = 29) DSPN. RESULTS: We achieve improved nerve- fiber detection over previous results (91.7% sensitivity and specificity in identifying nerve-fiber pixels). Automatic quantification of nerve morphology shows a high correlation with previously reported, manually measured, features. Receiver Operating Characteristic (ROC) analysis of both manual and automatic measurement regimes resulted in similar results in distinguishing patients with DSPN from those without: AUC of about 0.77 and 72% sensitivity-specificity at the equal error rate point. CONCLUSION: Automated quantification of corneal nerves in CCM images provides a sensitive tool for identification of DSPN. Its performance is equivalent to manual quantification, while improving speed and repeatability. SIGNIFICANCE: CCM is a novel in vivo imaging modality that has the potential to be a noninvasive and objective image biomarker for peripheral neuropathy. Automatic quantification of nerve morphology is a major step forward in the early diagnosis and assessment of progression, and, in particular, for use in clinical trials to establish therapeutic benefit in diabetic and other peripheral neuropathies.

Primary Care Pathway for Childhood Asthma: Protocol for a Randomized Cluster-Controlled Trial.

BACKGROUND: Asthma is the most common chronic condition in children. For many, the disease is inadequately controlled, which can burden the lives of children and their families as well as the health care system. Improved use of the best available scientific evidence by primary care practitioners could reduce the need for hospital care and improve quality of life and asthma control, thereby reducing overall costs to society and families. OBJECTIVE: The Primary Care Pathway for Childhood Asthma aims to improve the management of children with asthma by (1) providing primary care practitioners with an electronic guide (a clinical pathway) incorporated into the patient's electronic medical record, and (2) providing train-the-trainer education to chronic disease management health professionals to promote the provision of asthma education in primary care. METHODS: The research will utilize a pragmatic cluster-controlled design, quantitative and qualitative research methodologies, and economic evaluation to assess the implementation of a pathway and education intervention in primary care. The intervention will be analyzed for effectiveness, and if the results are positive, a strategy will be developed to implement delivery to all primary care practices in Alberta. RESULTS: The research has been successfully funded and ethics approvals have been obtained. Practice recruitment began fall 2015, and we expect all study-related activities to be concluded by March 2018. CONCLUSIONS: The proposed pathway and education intervention has the potential to improve pediatric asthma management in Alberta. The intervention is anticipated to result in better quality of care for equal or lesser cost. CLINICALTRIAL: ClinicalTrials.gov NCT02481037; https://clinicaltrials.gov/ct2/show/NCT02481037 (Archived by WebCite at http://www.webcitation.org/6fPIQ02Ma).

Small nerve fiber quantification in the diagnosis of diabetic sensorimotor polyneuropathy: comparing corneal confocal microscopy with intraepidermal nerve fiber density.

OBJECTIVE: Quantitative assessment of small fiber damage is key to the early diagnosis and assessment of progression or regression of diabetic sensorimotor polyneuropathy (DSPN). Intraepidermal nerve fiber density (IENFD) is the current gold standard, but corneal confocal microscopy (CCM), an in vivo ophthalmic imaging modality, has the potential to be a noninvasive and objective image biomarker for identifying small fiber damage. The purpose of this study was to determine the diagnostic performance of CCM and IENFD by using the current guidelines as the reference standard. RESEARCH DESIGN AND METHODS: Eighty-nine subjects (26 control subjects and 63 patients with type 1 diabetes), with and without DSPN, underwent a detailed assessment of neuropathy, including CCM and skin biopsy. RESULTS: Manual and automated corneal nerve fiber density (CNFD) (P < 0.0001), branch density (CNBD) (P < 0.0001) and length (CNFL) (P < 0.0001), and IENFD (P < 0.001) were significantly reduced in patients with diabetes with DSPN compared with control subjects. The area under the receiver operating characteristic curve for identifying DSPN was 0.82 for manual CNFD, 0.80 for automated CNFD, and 0.66 for IENFD, which did not differ significantly (P = 0.14). CONCLUSIONS: This study shows comparable diagnostic efficiency between CCM and IENFD, providing further support for the clinical utility of CCM as a surrogate end point for DSPN.

Automatic generation of statistical pose and shape models for articulated joints.

Statistical analysis of motion patterns of body joints is potentially useful for detecting and quantifying pathologies. However, building a statistical motion model across different subjects remains a challenging task, especially for a complex joint like the wrist. We present a novel framework for simultaneous registration and segmentation of multiple 3-D (CT or MR) volumes of different subjects at various articulated positions. The framework starts with a pose model generated from 3-D volumes captured at different articulated positions of a single subject (template). This initial pose model is used to register the template volume to image volumes from new subjects. During this process, the Grow-Cut algorithm is used in an iterative refinement of the segmentation of the bone along with the pose parameters. As each new subject is registered and segmented, the pose model is updated, improving the accuracy of successive registrations. We applied the algorithm to CT images of the wrist from 25 subjects, each at five different wrist positions and demonstrated that it performed robustly and accurately. More importantly, the resulting segmentations allowed a statistical pose model of the carpal bones to be generated automatically without interaction. The evaluation results show that our proposed framework achieved accurate registration with an average mean target registration error of 0.34 ±0.27 mm. The automatic segmentation results also show high consistency with the ground truth obtained semi-automatically. Furthermore, we demonstrated the capability of the resulting statistical pose and shape models by using them to generate a measurement tool for scaphoid-lunate dissociation diagnosis, which achieved 90% sensitivity and specificity.

The accuracy of prostate volume measurement from ultrasound images: a quasi-Monte Carlo simulation study using magnetic resonance imaging.

Prostate volume is an important parameter to guide management of patients with benign prostatic hyperplasia (BPH) and to deliver clinical trial endpoints. Generally, simple 2D ultrasound (US) approaches are favoured despite the potential for greater accuracy afforded by magnetic resonance imaging (MRI) or complex US procedures. In this study, different approaches to estimate prostate size are evaluated with a simulation to select multiple organ cross-sections and diameters from 22 MRI-defined prostate shapes. A quasi-Monte Carlo (qMC) approach is used to simulate multiple probe positions and angles within prescribed limits resulting in a range of dimensions. The basic ellipsoid calculation which uses two scanning planes compares well to the MRI volume across the range of prostate shapes and sizes (R=0.992). However, using an appropriate linear regression model, accurate volume estimates can be made using prostate diameters calculated from a single scanning plane.

The hyper-envelope modeling interface (HEMI): a novel approach illustrated through predicting tamarisk (Tamarix spp.) habitat in the Western USA.

Habitat suitability maps are commonly created by modeling a species' environmental niche from occurrences and environmental characteristics. Here, we introduce the hyper-envelope modeling interface (HEMI), providing a new method for creating habitat suitability models using Bezier surfaces to model a species niche in environmental space. HEMI allows modeled surfaces to be visualized and edited in environmental space based on expert knowledge and does not require absence points for model development. The modeled surfaces require relatively few parameters compared to similar modeling approaches and may produce models that better match ecological niche theory. As a case study, we modeled the invasive species tamarisk (Tamarix spp.) in the western USA. We compare results from HEMI with those from existing similar modeling approaches (including BioClim, BioMapper, and Maxent). We used synthetic surfaces to create visualizations of the various models in environmental space and used modified area under the curve (AUC) statistic and akaike information criterion (AIC) as measures of model performance. We show that HEMI produced slightly better AUC values, except for Maxent and better AIC values overall. HEMI created a model with only ten parameters while Maxent produced a model with over 100 and BioClim used only eight. Additionally, HEMI allowed visualization and editing of the model in environmental space to develop alternative potential habitat scenarios. The use of Bezier surfaces can provide simple models that match our expectations of biological niche models and, at least in some cases, out-perform more complex approaches.

The impacts of an invasive species citizen science training program on participant attitudes, behavior, and science literacy.

Citizen science can make major contributions to informal science education by targeting participants' attitudes and knowledge about science while changing human behavior towards the environment. We examined how training associated with an invasive species citizen science program affected participants in these areas. We found no changes in science literacy or overall attitudes between tests administered just before and after a one-day training program, matching results from other studies. However, we found improvements in science literacy and knowledge using context-specific measures and in self-reported intention to engage in pro-environmental activities. While we noted modest change in knowledge and attitudes, we found comparison and interpretation of these data difficult in the absence of other studies using similar measures. We suggest that alternative survey instruments are needed and should be calibrated appropriately to the pre-existing attitudes, behavior, and levels of knowledge in these relatively sophisticated target groups.

Automatic inference and measurement of 3D carpal bone kinematics from single view fluoroscopic sequences.

We present a novel framework for estimating the 3D poses and shapes of the carpal bones from single view fluoroscopic sequences. A hybrid statistical model representing both the pose and shape variation of the carpal bones is built, based on a number of 3D CT data sets obtained from different subjects at different poses. Given a fluoroscopic sequence, the wrist pose, carpal bone pose and bone shapes are estimated iteratively by matching the statistical model with the 2D images. A specially designed cost function enables smoothed parameter estimation across frames and constrains local bone pose with a penalty term. We have evaluated the proposed method on both simulated data and real fluoroscopic sequences and demonstrated that the relative poses of carpal bones can be accurately estimated. One condition that may be assessed using this measurement is dissociation, where the distance between the bones is larger than normal. Scaphoid-Lunate dissociation is one of the most common of these. The error of the measured 3D Scaphoid-Lunate distances were 0.75±0.50 mm for simulated data (25 subjects) and 0.93±0.47 mm for real data (15 subjects). We also propose a method for constructing a "standard" pathology measurement tool for automatically detecting Scaphoid-Lunate dissociation conditions, based on single-view fluoroscopic sequences. For the simulated data, it produced 100% sensitivity and specificity. For the real data, it achieved 83% sensitivity and 78% specificity.

Biological impact of divergent land management practices on tomato crop health.

Development of sustainable food systems is contingent upon the adoption of land management practices that can mitigate damage from soilborne pests. Five diverse land management practices were studied for their impacts on Fusarium wilt (Fusarium oxysporum f. sp. lycopersici), galling of roots by Meloidogyne spp. and marketable yield of tomato (Solanum lycopersicum) and to identify associations between the severity of pest damage and the corresponding soil microbial community structure. The incidence of Fusarium wilt was >14% when tomato was cultivated following 3 to 4 years of an undisturbed weed fallow or continuous tillage disk fallow rotation and was >4% after 3 to 4 years of bahiagrass (Paspalum notatum) rotation or organic production practices that included soil amendments and cover crops. The incidence of Fusarium wilt under conventional tomato production with soil fumigation varied from 2% in 2003 to 15% in 2004. Repeated tomato cultivation increased Fusarium wilt by 20% or more except when tomato was grown using organic practices, where disease remained less than 3%. The percent of tomato roots with galls from Meloidogyne spp. ranged from 18 to 82% in soil previously subjected to a weed fallow rotation and 7 to 15% in soil managed previously as a bahiagrass pasture. Repeated tomato cultivation increased the severity of root galling in plots previously subjected to a conventional or disk fallow rotation but not in plots managed using organic practices, where the percentage of tomato roots with galls remained below 1%. Marketable yield of tomato exceeded 35 Mg ha(-1) following all land management strategies except the strip-tillage/bahiagrass program. Marketable yield declined by 11, 14, and 19% when tomato was grown in consecutive years following a bahiagrass, weed fallow, and disk rotation. The composition of fungal internal transcribed spacer 1 (ITS1) and bacterial 16S rDNA amplicons isolated from soil fungal and bacterial communities corresponded with observed differences in the incidence of Fusarium wilt and severity of root galling from Meloidogyne spp. and provided evidence of an association between the effect of land management practices on soil microbial community structure, severity of root galling from Meloidogyne spp., and the incidence of Fusarium wilt.

Regional data refine local predictions: modeling the distribution of plant species abundance on a portion of the central plains.

Species distribution models are frequently used to predict species occurrences in novel conditions, yet few studies have examined the consequences of extrapolating locally collected data to regional landscapes. Similarly, the process of using regional data to inform local prediction for species distribution models has not been adequately evaluated. Using boosted regression trees, we examined errors associated with extrapolating models developed with locally collected abundance data to regional-scale spatial extents and associated with using regional data for predictions at a local extent for a native and non-native plant species across the northeastern central plains of Colorado. Our objectives were to compare model results and accuracy between those developed locally and extrapolated regionally, those developed regionally and extrapolated locally, and to evaluate extending species distribution modeling from predicting the probability of presence to predicting abundance. We developed models to predict the spatial distribution of plant species abundance using topographic, remotely sensed, land cover and soil taxonomic predictor variables. We compared model predicted mean and range abundance values to observed values between local and regional. We also evaluated model prediction performance based on Pearson's correlation coefficient. We show that: (1) extrapolating local models to regional extents may restrict predictions, (2) regional data can help refine and improve local predictions, and (3) boosted regression trees can be useful to model and predict plant species abundance. Regional sampling designed in concert with large sampling frameworks such as the National Ecological Observatory Network may improve our ability to monitor changes in local species abundance.

Inferring 3D kinematics of carpal bones from single view fluoroscopic sequences.

We present a novel framework for inferring 3D carpal bone kinematics and bone shapes from a single view fluoroscopic sequence. A hybrid statistical model representing both the kinematics and shape variation of the carpal bones is built, based on a number of 3D CT data sets obtained from different subjects at different poses. Given a fluoroscopic sequence, the wrist pose, carpal bone kinematics and bone shapes are estimated iteratively by matching the statistical model with the 2D images. A specially designed cost function enables smoothed parameter estimation across frames. We have evaluated the proposed method on both simulated data and real fluoroscopic sequences. It was found that the relative positions between carpal bones can be accurately estimated, which is potentially useful for detection of conditions such as scapholunate dissociation.

Project Lazarus: community-based overdose prevention in rural North Carolina.

BACKGROUND: In response to some of the highest drug overdose death rates in the country, Project Lazarus developed a community-based overdose prevention program in Western North Carolina. The Wilkes County unintentional poisoning mortality rate was quadruple that of the state's in 2009 and due almost exclusively to prescription opioid pain relievers, including fentanyl, hydrocodone, methadone, and oxycodone. The program is ongoing. METHODS: The overdose prevention program involves five components: community activation and coalition building; monitoring and surveillance data; prevention of overdoses; use of rescue medication for reversing overdoses by community members; and evaluating project components. Principal efforts include education of primary care providers in managing chronic pain and safe opioid prescribing, largely through the creation of a tool kit and face-to-face meetings. RESULTS: Preliminary unadjusted data for Wilkes County revealed that the overdose death rate dropped from 46.6 per 100,000 in 2009 to 29.0 per 100,000 in 2010. There was a decrease in the number of victims who received prescriptions for the substance implicated in their fatal overdose from a Wilkes County physician; in 2008, 82% of overdose decedents received a prescription for an opioid analgesic from a Wilkes prescriber compared with 10% in 2010. CONCLUSIONS: While the results from this community-based program are preliminary, the number and nature of prescription opioid overdose deaths in Wilkes County changed during the intervention. Further evaluation is required to understand the localized effect of the intervention and its potential for replication in other areas.

Federated or cached searches: Providing expected performance from multiple invasive species databases.

Invasive species are a universal global problem, but the information to identify them, manage them, and prevent invasions is stored around the globe in a variety of formats. The Global Invasive Species Information Network is a consortium of organizations working toward providing seamless access to these disparate databases via the Internet. A distributed network of databases can be created using the Internet and a standard web service protocol. There are two options to provide this integration. First, federated searches are being proposed to allow users to search "deep" web documents such as databases for invasive species. A second method is to create a cache of data from the databases for searching. We compare these two methods, and show that federated searches will not provide the performance and flexibility required from users and a central cache of the datum are required to improve performance.

Repeatability of measuring corneal subbasal nerve fiber length in individuals with type 2 diabetes.

PURPOSE: To analyze the repeatability of measuring nerve fiber length (NFL) from images of the human corneal subbasal nerve plexus using semiautomated software. METHODS: Images were captured from the corneas of 50 subjects with type 2 diabetes mellitus who showed varying severity of neuropathy, using the Heidelberg Retina Tomograph 3 with Rostock Corneal Module. Semiautomated nerve analysis software was independently used by two observers to determine NFL from images of the subbasal nerve plexus. This procedure was undertaken on two occasions, 3 days apart. RESULTS: The intraclass correlation coefficient values were 0.95 (95% confidence intervals: 0.92-0.97) for individual subjects and 0.95 (95% confidence intervals: 0.74-1.00) for observer. Bland-Altman plots of the NFL values indicated a reduced spread of data with lower NFL values. The overall spread of data was less for (a) the observer who was more experienced at analyzing nerve fiber images and (b) the second measurement occasion. CONCLUSIONS: Semiautomated measurement of NFL in the subbasal nerve fiber layer is highly repeatable. Repeatability can be enhanced by using more experienced observers. It may be possible to markedly improve repeatability when measuring this anatomic structure using fully automated image analysis software.