Elia Vecellio

Binocular depth discrimination and estimation beyond interaction space

The benefits of binocular vision have been debated throughout the history of vision science yet few studies have considered its contribution beyond a viewing distance of a few meters. In the first set of experiments, we compared monocular and binocular performance on depth interval estimation and discrimination tasks at 4.5, 9.0 or 18.0 m. Under monocular conditions, perceived depth was significantly compressed. Binocular depth estimates were much nearer to veridical although also compressed. Regression-based precision measures were much more precise for binocular compared to monocular conditions (ratios between 2.1 and 48). We confirm that stereopsis supports reliable depth discriminations beyond typical laboratory distances. Furthermore, binocular vision can significantly improve both the accuracy and precision of depth estimation to at least 18 m. In another experiment, we used a novel paradigm that allowed the presentation of real binocular disparity stimuli in the presence of rich environmental cues to distance but not interstimulus depth. We found that the presence of environmental cues to distance greatly enhanced stereoscopic depth constancy at distances of 4.5 and 9.0 m. We conclude that stereopsis is an effective cue for depth discrimination and estimation for distances beyond those traditionally assumed. In normal environments, distance information from other sources such as perspective can be effective in scaling depth from disparity.

The role of binocular vision in walking

Despite the extensive investigation of binocular and stereoscopic vision, relatively little is known about its importance in natural visually guided behavior. In this paper, we explored the role of binocular vision when walking over and around obstacles. We monitored eye position during the task as an indicator of the difference between monocular and binocular performances. We found that binocular vision clearly facilitates walking performance. Walkers were slowed by about 10% in monocular vision and raised their foot higher when stepping over obstacles. Although the location and sequence of the fixations did not change in monocular vision, the timing of the fixations relative to the actions was different. Subjects spent proportionately more time fixating the obstacles and fixated longer while guiding foot placement near an obstacle. The data are consistent with greater uncertainty in monocular vision, leading to a greater reliance on feedback in the control of the movements.

Monitoring the impact of the electronic medical record on the quality of laboratory test ordering practices.

The aim of this study was to examine the impact of the Electronic Medical Record (EMR) on the quality of laboratory test orders made by clinicians. The study assessed the type and frequency of pre-analytical laboratory test order errors that were associated with the EMR across three hospitals and one pathology service. This involved a retrospective audit of the laboratory error logs for the period 1 March 2010 to 9 October 2011. Test order problems associated with the EMR occurred at a total rate of 1.34 per 1000 test order episodes across the three hospitals. In the majority of cases these errors were caused by the inappropriate use of the EMR system by clinicians. The errors resulted in increased data entry time for laboratory staff in the Central Specimen Reception area and led to a median increase of 181 minutes in test turnaround times for those test orders. The study highlights the importance of monitoring and comparing the impact of EMR systems in different locations over time in order to identify (and act upon) factors that can adversely impact on the effectiveness of pathology laboratory processes.

Making sense of a haemolysis monitoring and reporting system: a nationwide longitudinal multimethod study of 68 Australian laboratory participant organisations

Abstract Background: The key incident monitoring and management systems (KIMMS) quality assurance program monitors incidents in the pre- and postanalytical phases of testing in medical laboratories. Haemolysed specimens have been found to be the most frequent preanalytical error and have major implications for patient care. The aims of this study were to assess the suitability of KIMMS for quality reporting of haemolysis and to devise a meaningful method for reporting and monitoring haemolysis. Methods: A structured survey of 68 Australian KIMMS laboratory participant organisations was undertaken. Quarterly haemolysis reports (2011–2014) were analysed. Results: Among 110 million accessions reported, haemolysis rates varied according to the reporting methods that participants used for assigning accessions (16% of participants reported haemolysis by specimen and 83% reported by episode) and counting haemolysis rejections (61% by specimen, 35% by episode and 3% by test). More than half of the participants (56%) assigned accessions by episode and counted rejections by specimen. For this group, the average haemolysis rate per 100,000 episodes was 177 rejected specimens with the average rate varying from 100 to 233 over time. The majority of participants (91%) determined rejections using the haemolysis index. Two thirds of participants (66%) recorded the haemolysis manually in laboratory information systems. Conclusions: KIMMS maintains the largest longitudinal haemolysis database in the world. However, as a means of advancing improvements in the quality of the preanalytical laboratory process, there is a need to standardise reporting methods to enable robust comparison of haemolysis rejection rates across participant laboratories.

Key factors influencing the incidence of hemolysis: A critical appraisal of current evidence

Abstract Hemolysis is a leading cause of pre-analytical laboratory errors. The identification of contributing factors is an important step towards the development of effective practices to reduce and prevent hemolysis. We performed a review of PUBMED, Embase, Medline and CINAHL to identify articles published between January 2000 and August 2016 that identified factors influencing in vitro hemolysis rates. The 40 studies included in this review provide excellent evidence that hemolysis rates are higher in Emergency Departments (EDs), for non-antecubital draws, for specimens drawn using an intravenous catheter compared to venipuncture and for samples transported by pneumatic tube compared to by hand. There is also good evidence that hemolysis rates are higher when specimens are not collected by professional phlebotomists, larger volume specimen tubes are used, specimen tubes are filled less than halfway and tourniquet time is greater than one minute. The results of this review suggest that hospitals and clinical laboratories should consider deploying phlebotomists in EDs, drawing all blood through a venipuncture, using the antecubital region as the optimum blood collection site and transporting specimens by laboratory assistant/other personnel, or if this in not practical, ensuring that pneumatic transport systems are validated, maintained and monitored. Studies also recommend making hemolysis a hospital-wide issue and ensuring high-quality staff training and adherence to standard operating procedures to reduce hemolysis rates. Awareness of the factors that influence hemolysis rates, and adoption of strategies to mitigate these risk factors, is an important step towards creating quality practices to reduce hemolysis rates and improve the quality of patient care.

Data quality associated with handwritten laboratory test requests: classification and frequency of data-entry errors for outpatient serology tests.

Objective: Manual data-entry of handwritten laboratory test requests into electronic information systems has implications for data accuracy. This study sought to identify the types and number of errors occurring for handwritten serology test requests received from outpatient clinics. Methods: A 15-day audit at a serology laboratory in Sydney, Australia, compared the content of all transcribed serology outpatient test requests in the laboratory information system with the handwritten request form. Results: One or more errors were detected in 67/627 (10.7%) audited requests (N=68 errors). Fifty-one of the errors (75.0%) were transcription errors: the wrong test was transcribed in 40/68 cases (58.8%) – ten of these occurred when the abbreviations ‘HBsAb’ and ‘HBsAg’ were confounded for one another – and transcribed requests were missing a test in 11/68 cases (16.2%). The remaining 17 non-transcription errors (25.0%) described request forms not signed by the ordering clinician, mislabelled specimens, and wrong tests due to computer algorithm errors. Conclusions: Manual data-entry of handwritten serology requests is an error-prone process. Electronic ordering has the potential to eliminate illegible handwriting and transcription errors, thus improving data accuracy in hospital information systems.

Orientation contrast and entropy contrast in the genesis of subjective contours along thin lines.

Subjective contours are widely considered to be an aspect of the perception of occlusion, but considerations of occlusion do not always drive predictions of their strength. Occluding surfaces have no necessary relationship to the contours they occlude, yet it is commonly predicted that subjective contours will be strongest for inducer alignments that are orthogonal to inducer orientations. In several papers we have proposed that a lack of relationship between inducers and their alignment promotes seeing subjective contours. We explore this further here using horizontal or near-horizontal thin-line inducers arranged vertically with linearly aligned terminations along central gaps. Subjective contour strength was measured using the method of paired comparison in two experiments. The weakest subjective contours were found when the gap was orthogonal to the inducers and parallel to the outer edges of the line set. Subjective contours were strengthened by orientation contrast, defined either as a nonorthogonal relationship between the gap and the inducers or as nonparallelism between the gap and the outer alignments of the inducers. The effect was replicated at both high and low line densities. We also confirmed a strong effect of high inducer entropy (variations in inducer orientation and separation) with thin-line inducers. The results support the view that the lack of a relationship of alignments to what is aligned is a major determinant of subjective contour strength.

The Impact of an Electronic Medical Record on Repeat Laboratory Test Ordering Across Four Australian Hospitals.

In this study we examined the impact of an Electronic Medical Record (EMR) on repeat test rates (i.e., the same test ordered within a specified window of time) for a commonly ordered set of laboratory tests; Electrolytes, Urea, Creatinine [EUC], Full Blood Counts [FBC] and Liver Function Tests [LFT]. The results point to the potential that timely, evidence-based electronic decision support features can have on the efficiency and effectiveness of the pathology laboratory process and its contribution to quality patient care.

What is the effect of electronic pathology ordering on test re-ordering patterns for paediatric patients?

Electronic ordering systems have the potential to enhance the efficient utilisation of pathology services. The aim of this study was to assess the effect of electronic pathology ordering on repeat test ordering for paediatric patients (ages 0 to 18 years) who were in intensive care units (ICUs) and non-ICU wards. The dataset described 85,728 pathology tests ordered for 5,073 children before and after the implementation of electronic ordering. This study showed that, for children in ICUs, the repeat test order rate was significantly lower for electronic orders than for paper-based orders. Similarly, the rate of repeat tests ordered within short intervals (up to 23-hours), for children older than one-year in non-ICU wards, was lower for electronic ordering than for paper ordering. The proportion of repeat tests occurring within one-hour of the previous test was consistently lower for tests ordered using electronic ordering than it was for tests ordered using the paper based system for patients older than one-year in all wards and for patients under one-year in ICUs. These results suggest that features of the electronic system, including alerts about previously ordered tests and the availability of information about previous orders, can help clinicians to identify and reduce unnecessary repeat tests.

Examination of changes in pathology tests ordered by Diagnosis-Related Group (DRGs) following CPOE introduction.

Electronic test ordering, via the Electronic Medical Record (EMR), which incorporates computerised provider order entry (CPOE), is widely considered as a useful tool to support appropriate pathology test ordering. Diagnosis-related groups (DRGs) are clinically meaningful categories that allow comparisons in pathology utilisation by patient groups by controlling for many potentially confounding variables. This study used DRG data linked to pathology test data to examine changes in rates of test ordering across four years coinciding with the introduction of an EMR in six hospitals in New South Wales, Australia. This method generated a list of high pathology utilisation DRGs. We investigated patients with a Chest pain DRG to examine whether tests rates changed for specific test groups by hospital emergency department (ED) pre- and post-EMR. There was little change in testing rates between EDs or between time periods pre- and post-EMR. This is a valuable method for monitoring the impact of EMR and clinical decision support on test order rates.