Smart Glasses for Radial Arterial Catheterization in Pediatric Patients: A Randomized Clinical Trial.

BACKGROUND: Hand-eye coordination and ergonomics are important for the success of delicate ultrasound-guided medical procedures. These can be improved using smart glasses (head-mounted display) by decreasing the head movement on the ultrasound screen. The hypothesis was that the smart glasses could improve the success rate of ultrasound-guided pediatric radial arterial catheterization. METHODS: This prospective, single-blinded, randomized controlled, single-center study enrolled pediatric patients (n = 116, age less than 2 yr) requiring radial artery cannulation during general anesthesia. The participants were randomized into the ultrasound screen group (control) or the smart glasses group. After inducing general anesthesia, ultrasound-guided radial artery catheterization was performed. The primary outcome was the first-attempt success rate. The secondary outcomes included the first-attempt procedure time, the overall complication rate, and operators' ergonomic satisfaction (5-point scale). RESULTS: In total, 116 children were included in the analysis. The smart glasses group had a higher first-attempt success rate than the control group (87.9% [51/58] vs. 72.4% [42/58]; P = 0.036; odds ratio, 2.78; 95% CI, 1.04 to 7.4; absolute risk reduction, -15.5%; 95% CI, -29.8 to -12.8%). The smart glasses group had a shorter first-attempt procedure time (median, 33 s; interquartile range, 23 to 47 s; range, 10 to 141 s) than the control group (median, 43 s; interquartile range, 31 to 67 s; range, 17 to 248 s; P = 0.007). The overall complication rate was lower in the smart glasses group than in the control group (5.2% [3/58] vs. 29.3% [17/58]; P = 0.001; odds ratio, 0.132; 95% CI, 0.036 to 0.48; absolute risk reduction, 24.1%; 95% CI, 11.1 to 37.2%). The proportion of positive ergonomic satisfaction (4 = good or 5 = best) was higher in the smart glasses group than in the control group (65.5% [38/58] vs. 20.7% [12/58]; P <0.001; odds ratio, 7.3; 95% CI, 3.16 to 16.8; absolute risk reduction, -44.8%; 95% CI, -60.9% to -28.8%). CONCLUSIONS: Smart glasses-assisted ultrasound-guided radial artery catheterization improved the first-attempt success rate and ergonomic satisfaction while reducing the first-attempt procedure time and overall complication rates in small pediatric patients.

Human factors/ergonomics to support the design and testing of rapidly manufactured ventilators in the UK during the COVID-19 pandemic.

BACKGROUND: This paper describes a rapid response project from the Chartered Institute of Ergonomics & Human Factors (CIEHF) to support the design, development, usability testing and operation of new ventilators as part of the UK response during the COVID-19 pandemic. METHOD: A five-step approach was taken to (1) assess the COVID-19 situation and decide to formulate a response; (2) mobilise and coordinate Human Factors/Ergonomics (HFE) specialists; (3) ideate, with HFE specialists collaborating to identify, analyse the issues and opportunities, and develop strategies, plans and processes; (4) generate outputs and solutions; and (5) respond to the COVID-19 situation via targeted support and guidance. RESULTS: The response for the rapidly manufactured ventilator systems (RMVS) has been used to influence both strategy and practice to address concerns about changing safety standards and the detailed design procedure with RMVS manufacturers. CONCLUSION: The documents are part of a wider collection of HFE advice which is available on the CIEHF COVID-19 website (https://covid19.ergonomics.org.uk/).

Postural ergonomics and work-related musculoskeletal disorders in neurosurgery: lessons from an international survey.

BACKGROUND: Work-related musculoskeletal disorders (WMSDs) affect a significant percentage of the neurosurgical workforce. The aim of the current questionnaire-based study was to examine the prevalence of WMSDs amongst neurosurgeons, identify risk factors, and study the views of neurosurgeons regarding ergonomics. METHODS: From June to August 2020, members of the "European Association of Neurosurgical Societies," the "Neurosurgery Research Listserv," and the "Latin American Federation of Neurosurgical Societies" were asked to complete an electronic questionnaire on the topics of WMSDs and ergonomics. RESULTS: A total of 409 neurosurgeons responded to the survey, with a 4.7 male to female ratio. Most of the surgeons worked in Europe (76.9%) in academic public hospitals. The vast majority of the participants (87.9%) had experienced WMSDs, mainly affecting the shoulder, neck, and back muscles. The most common operations performed by the participants were "Craniotomy for convexity/intrinsic tumors" (24.1%) and "Open lumbar basic spine" (24.1%). Neurosurgeons agreed that ergonomics is an underexposed area in the neurosurgical field (84.8%) and that more resources should be spend (87.3%) and training curricula changes should be made (78.3%) in order to alleviate the burden of WMSDs on neurosurgeons. Univariate analysis did not reveal any associations between the development of WMSDs and age, gender, tenure, average duration of operation, operating time per week, type of operation, and surgical approach. CONCLUSIONS: The problem of WMSDs ought to be more closely addressed and managed by the neurosurgical community. More studies ought to be designed to investigate specific ergonomic parameters in order to formulate practice recommendations.

Workforce perceptions of human factors as indicators of plant reliability and process safety.

Human factors, as perceived by the maintenance workforce, were used as the measure for comparing work areas within a petroleum company. These factors were then compared to an objective measure of reliability (Mean Time Between Failures) in order to determine which factors would be most predictive of plant reliability and process safety. Maintenance personnel were surveyed using scales based on Problem-solving, Vigilance, Design and maintenance, Job-related feedback and Information about change. Analysis of Variance was used to assess the strength of these variables in relation to Reliability Level. Significant differences were observed between different reliability levels based on workforce perceptions of problem-solving requirements and the design and maintainability of plant. Conclusions were that perceptions of human factors in the workplace can be predictive of group-level performance, and that if issues relating to design and maintainability are not addressed at the design stage, greater problem-solving abilities will be required from maintenance personnel. Practitioner summary: Workforce perceptions of plant performance could provide a statistically valid measure of current and future reliability. A survey of perceptions of human factors was conducted with maintenance personnel in a petroleum company. Results indicated significant relationships between reliability and requirements for Problem-solving, as well as Design and Maintenance of equipment. Abbreviations: HFIT: human factors investigation tool, FPSO: floating production, storage and offtake, MTBF: mean time between failures, CPS: cognitive problem- solving, WDS: work design questionnaire, SPSS: statistical package for the social sciences, PAF: principal axis factoring, ANOVA: analysis of variance, ANCOVA: analysis of co-variance, M: mean, SD: standard deviation.

Ergonomics in Dermatologic Surgery: Lessons Learned Across Related Specialties and Opportunities for Improvement.

BACKGROUND: As the practice of dermatology becomes increasingly procedurally based, there is a concordant rise in musculoskeletal injury (MSI) risk. Dermatologic surgeons are most susceptible and, although the majority suffer from MSI, few have received any formal ergonomics training. This stems from a lack of awareness of this troubling trend and a paucity of research and education on the ergonomics of dermatologic surgery. OBJECTIVE: To highlight pertinent ergonomics principles and strategies from other specialties that could be translated into dermatology, and to synthesize general recommendations aimed at reducing MSI among dermatologic surgeons. MATERIALS AND METHODS: A comprehensive search of the PubMed and Cochrane Reviews databases from 1975 to 2019 was conducted, using a combination of ergonomics-related search terms, generating 6 publications from the dermatology literature and 58 from the fields of dentistry, medicine, and select surgical subspecialties. RESULTS: This multidisciplinary approach yielded multiple interventions that could be applied directly (i.e., adequate lighting, adjustable operating tables, and surgical seat heights) or indirectly pending further investigation into their feasibility (i.e., video displays of the surgical field to allow neutral head and neck postures). CONCLUSION: Although much can be learned from decades of prior ergonomics research from other specialties, considerations that are unique to dermatology remain and must be addressed with specialty-specific research.

Ergonomics and musculoskeletal disorders in neurosurgery: a systematic review.

BACKGROUND: Work-related musculoskeletal disorders (WMSDs) are a growing and probably undervalued concern for neurosurgeons and spine surgeons, as they can impact their quality of life and career length. This systematic review aims to ascertain this association and to search for preventive measures. METHODS: We conducted a PRISMA-P-based review on ergonomics and WMSDs in neurosurgery over the last 15 years. Twelve original articles were included, of which 6 focused on spine surgery ergonomics, 5 cranio-facial surgery (mainly endoscopic), and one on both domains. RESULTS: We found a huge methodological and content diversity among studies with 5 surveys, 3 cross-sectional studies, 2 retrospective cohorts, and 2 technical notes. Spine surgeons have sustained neck flexion and neglect their posture during surgery. In a survey, low back pain was found in 62% of surgeons, 31% of them with a diagnosed lumbar disc herniation, and 23% of surgery rate. Pain in the neck (59%), shoulder (49%), finger (31%), and wrist (25%) are more frequent than in the general population. Carpal tunnel syndrome showed a linear relationship with increasing cumulative hours of spine surgery practice. Among cranial procedures, endoscopy was also significantly related to shoulder pain while pineal region surgery received some attempts to optimize ergonomics. CONCLUSIONS: Ergonomics in neurosurgery remains underreported and lack attention from surgeons and authorities. Improvements shall target postural ergonomics, equipment design, weekly schedule adaptation, and exercise.

Tertiary education in ergonomics and human factors: quo vadis?

In 2019, the Human Factors and Ergonomics (HFE) discipline turned 70; to celebrate, an international group of academics and educators have reflected on the status of HFE tertiary education across the globe. This paper draws on presentations and discussions from the 20th Triennial International Ergonomics Association (IEA) conference and considers the implications for HFE education programmes. Past, current, and future challenges are outlined and discussed with examples from different countries and programmes. This paper builds on 2012 strategy proposed by Dul and colleagues, to strengthen the demand, and application, of the HFE discipline and profession. It provides a considered set of reflections, noting the range of structural issues and financial pressures within the tertiary education system that create challenges for the viability of specialist programmes such as HFE. A need exists for the broader profession to collaborate and share innovations in HFE programme development, to ensure sustainable HFE education programmes. Practitioner summary: A range of structural issues and financial pressures exist within the tertiary education system that creates challenges for the viability of specialist programmes such as HFE. A need exists for the broader profession to collaborate and share innovations in HFE programme development, to ensure sustainable HFE education programmes. Abbreviation: HFE: Human Factors and Ergonomics; IEA: International Ergonomics Association; CIEHF: Chartered Institute of Ergonomics & Human Factors; UX: User Experience; CREE: Centre for Registration of European Ergonomist; BRICSplus: Brazil, Russia, India, China and South Africa; MOOCS: Massive Open Online Courses; STST: socio technical systems theory; LMIC: low and middle-income countries.

Health and productivity at work: which active workstation for which benefits: a systematic review.

In order to reduce sedentary behaviour at work, research has examined the effectiveness of active workstations. However, despite their relevance in replacing conventional desks, the comparison between types of active workstations and their respective benefits remains unclear. The purpose of this review article is thus to compare the benefits between standing, treadmill and cycling workstations. Search criteria explored Embase, PubMed and Web of Science databases. The review included studies concerning adults using at least two types of active workstations, evaluating biomechanical, physiological work performance and/or psychobiological outcomes. Twelve original articles were included. Treadmill workstations induced greater movement/activity and greater muscular activity in the upper limbs compared with standing workstations. Treadmill and cycling workstations resulted in elevated heart rate, decreased ambulatory blood pressure and increased energy expenditure during the workday compared with standing workstations. Treadmill workstations reduced fine motor skill function (ie, typing, mouse pointing and combined keyboard/mouse tasks) compared with cycling and standing workstations. Cycling workstations resulted in improved simple processing task speeds compared with standing and treadmill workstations. Treadmill and cycling workstations increased arousal and decreased boredom compared with standing workstations. The benefits associated with each type of active workstation (eg, standing, treadmill, cycling) may not be equivalent. Overall, cycling and treadmill workstations appear to provide greater short-term physiological changes than standing workstations that could potentially lead to better health. Cycling, treadmill and standing workstations appear to show short-term productivity benefits; however, treadmill workstations can reduce the performance of computer tasks.

Are Measures of Postural Behavior Using Motion Sensors in Seated Office Workers Reliable?

OBJECTIVE: In this study, the reliability of measures of upper body postural behavior (head, thorax, neck, and arm) during sustained office work was evaluated. BACKGROUND: Although there has been a substantial body of research examining the technical aspects of posture measurement in office workers using motion sensors, there is a paucity of literature examining whether posture-related behaviors are actually consistent among office workers in the field on different days and times. METHOD: Thirty one office workers performed their usual work for three, 1-hr sessions (two morning sessions and one afternoon session) while wearing wireless motion sensors. Reliability coefficients of the derived measures of postural behavior were calculated. RESULTS: Most (30/31) of the postural behavior measures demonstrated modest to excellent reliability (ICC 2.1: 0.48-0.84). Reliability appeared to be mildly affected by factors such as the time of day recordings were taken and variations in desk setups. CONCLUSION: The findings suggest these measures may be a reliable method for evaluating postural behavior in the office work environment in future studies. APPLICATION: Postural measurement using a technical motion sensor described an acceptable reliability to be used for risk assessment in the workplace. Consideration of assessment time and desk setting would increase the accuracy of postural measurement.

Return to work after rehabilitation in chronic low back pain workers. Does the interprofessional collaboration work?

The objective of this study was to assess the workplace information collected and shared between professionals of the centers and occupational health professionals during functional restoration programs intended to chronic low back pain patients. A descriptive study carried out by a questionnaire sent to the French rehabilitation centers offering a functional restoration program. Data collection focused on the kinds of professionals involved in programs, professionals who approach work issues, work analysis, social and occupational information collected, existence of a specific work rehabilitation program, frequency of and methods for sharing information with occupational health professionals. Occupational information was mostly collected at inclusion during an individual interview by the rehabilitation physicians, social workers, and occupational therapists. Workplace environment was the most poorly discussed aspect. A minority of centers adapted their programs regarding these information. Information sharing with occupational physicians was mostly through the patient and was influenced by the presence of an ergonomist or of an occupational physician in the team. The study found poor interest about work environment and that the cooperation between practitioners in disability management remains limited. The various practitioners' cultures and interests may be a brake on cooperation and exchange of information.

Workplace interventions to improve sitting posture: A systematic review.

PURPOSE: Evaluate the effectiveness of workplace interventions to improve sitting posture of workers that spend long periods of time seated at a visual display terminal. METHODS: A systematic review of randomised controlled trials, non-randomised controlled trials and single-group intervention trials featuring workplace interventions with pre- and follow-up measurements of sitting posture was conducted (registered in PROSPERO, CRD#42015027648). Nine databases were searched for studies available between January 2005 and February 2016. RESULTS: 2519 articles were screened with 12 studies meeting the inclusion criteria. The included studies featured various ergonomic workplace interventions and comprised 4 randomised controlled trial (n=457), 2 non-randomised controlled trials (n=416) and 6 single-group intervention trials (n=328). Due to clinical and methodological heterogeneity, pooling of data was not completed and a narrative summary of findings was developed using the Grading of Recommendations Assessment Development and Evaluation (GRADE) framework. The evidence for four review outcomes was assessed with medium to large positive improvements obtained for the majority of studies investigating changes to gross sitting posture, whereas mixed findings were obtained for more specific local segment assessments of sitting posture. The overall evidence quality for all review outcomes were identified as either 'low' or 'very low'. CONCLUSION: There is evidence which is limited in quality to indicate that ergonomic workplace interventions can improve gross sitting posture. More high quality research across a range of intervention types is required with longer follow-up durations and more advanced methods to assess sitting posture with greater frequency and less bias.

Key Recommendations from the MedtecHTA Project.

There are particular characteristics of Medical Devices, such as the device-user interaction, the incremental nature of innovation and the broader organizational impact that lead to additional challenges for health technology assessment (HTA). The project explored key aspects of the conduct and methods of HTA for MDs. Systematic reviews and original research studies were conducted to determine improvements in processes and methods that could enhance the potential for HTA and optimize the diffusion of MDs. Regulatory processes for MDs should be more closely aligned, the HTA evaluative framework should be harmonized and processes for conditional coverage and evidence development should be used. The methods for HTA should consider MDs as complex interventions, require the establishment of high quality registries, consider an iterative approach to the evaluation over time, recognize and allow for the particular characteristics of devices and use appropriate approaches for confounder adjustment in comparative effectiveness studies. To optimize the diffusion, a common classification should be developed across countries in order to facilitate international comparisons, factors driving diffusion should be explored in HTA reports and physicians' personal goals and motivation should be better understood. The key recommendations of the MedtecHTA project should improve the conduct and use of HTA for MDs. © 2017 The Authors. Health Economics published by John Wiley & Sons, Ltd.

Confirmatory Factor and Rasch Analyses Support a Revised 14-Item Version of the Organizational, Policies, and Practices (OPP) Scale.

Background The long version of the organizational, policies and practices (OPP) had a high burden and short versions were developed to solve this drawback. The 11-item version showed promise, but the ergonomic subscale was deficient. The OPP-14 was developed by adding three additional items to the ergonomics subscale. The aim of this study is to evaluate the factor structure using confirmatory factor and Rasch analyses in healthy firefighters. Methods A sample of 261 firefighters (Mean age 42 years, 95 % male) were sampled. A confirmatory factor and Rasch analyses were used to assess the internal consistency, factor structure and other psychometric characteristics of revised OPP-14. Results The OPP-14 demonstrates sound factor structure and internal consistency in firefighters. Confirmatory factor analysis confirmed the consistency of the original 4-domain structure (CFI = 0.97, TLI = 0.96, and RMSEA = 0.053). The 5 items showing misfit initially with disordered thresholds were rescored. The four subscales satisfied Rasch expectations with well target and acceptable reliability. Conclusions The OPP-14 scale shows a promising factor structure in this sample and remediated deficits found in OPP-11. This version may be preferable for musculoskeletal concerns or work applications where ergonomic indicators are relevant.

Comparison of Sedentary Behaviors in Office Workers Using Sit-Stand Tables With and Without Semiautomated Position Changes.

OBJECTIVE: We compared usage patterns of two different electronically controlled sit-stand tables during a 2-month intervention period among office workers. BACKGROUND: Office workers spend most of their working time sitting, which is likely detrimental to health. Although the introduction of sit-stand tables has been suggested as an effective intervention to decrease sitting time, limited evidence is available on usage patterns of sit-stand tables and whether patterns are influenced by table configuration. METHOD: Twelve workers were provided with standard sit-stand tables (nonautomated table group) and 12 with semiautomated sit-stand tables programmed to change table position according to a preset pattern, if the user agreed to the system-generated prompt (semiautomated table group). Table position was monitored continuously for 2 months after introducing the tables, as a proxy for sit-stand behavior. RESULTS: On average, the table was in a "sit" position for 85% of the workday in both groups; this percentage did not change significantly during the 2-month period. Switches in table position from sit to stand were, however, more frequent in the semiautomated table group than in the nonautomated table group (0.65 vs. 0.29 hr-1; p = .001). CONCLUSION: Introducing a semiautomated sit-stand table appeared to be an attractive alternative to a standard sit-stand table, because it led to more posture variation. APPLICATION: A semiautomated sit-stand table may effectively contribute to making postures more variable among office workers and thus aid in alleviating negative health effects of extensive sitting.

Development of a Seating Comfort Questionnaire for Motorcycles.

Objective The aim of this study is to develop a reliable and valid Motorcycle Seating Comfort Questionnaire (MSCQ). Background Motorcycle seat development is an iterative process based on subjective evaluations; however, there are no established subjective tools for evaluation of seating comfort. Research also suggests that seating comfort in motorcycles is poor and needs improvement. The development of a MSCQ therefore is an important step that can enable further research and aid in improving the design of motorcycle seats. Method The MSCQ is developed following guidelines available in literature and referring to established questionnaires for seating comfort in passenger cars. The MSCQ is further refined based on pilot studies and interviews with experts. The final version of the MSCQ is then statistically evaluated for reliability and validity. The reliability is evaluated using a test-retest protocol with 31 volunteers. The validity is evaluated by comparing the ratings of the MSCQ with that of the Category Partitioning Scale (CP50 scale). The validity test is carried out with 15 volunteers evaluating five motorcycles using both scales. Results The results show that the MSCQ is reliable with a significant test-retest reliability coefficient ( r = 0.72, p < .01, n = 31) and internal consistency (Cronbach's α = 0.81, n = 31). The results also show that ratings of the MSCQ have a significant correlation ( r = -0.765, p < .05, n = 15) with that of CP50, establishing its validity. Conclusions A Motorcycle Seating Comfort Questionnaire is developed in this study with statistically established reliability and validity. Applications The MSCQ can be used as a tool for evaluation of seating comfort in motorcycles. The MSCQ can also form a basis for further research on motorcycle seating to develop prediction models and guidelines for the design of motorcycle seats.

Performance assessment of human resource by integration of HSE and ergonomics and EFQM management system.

Purpose The purpose of this paper is to present an integrated framework for performance evaluation and analysis of human resource (HR) with respect to the factors of health, safety, environment and ergonomics (HSEE) management system, and also the criteria of European federation for quality management (EFQM) as one of the well-known business excellence models. Design/methodology/approach In this study, an intelligent algorithm based on adaptive neuro-fuzzy inference system (ANFIS) along with fuzzy data envelopment analysis (FDEA) are developed and employed to assess the performance of the company. Furthermore, the impact of the factors on the company's performance as well as their strengths and weaknesses are identified by conducting a sensitivity analysis on the results. Similarly, a design of experiment is performed to prioritize the factors in the order of importance. Findings The results show that EFQM model has a far greater impact upon the company's performance than HSEE management system. According to the obtained results, it can be argued that integration of HSEE and EFQM leads to the performance improvement in the company. Practical implications In current study, the required data for executing the proposed framework are collected via valid questionnaires which are filled in by the staff of an aviation industry located in Tehran, Iran. Originality/value Managing HR performance results in improving usability, maintainability and reliability and finally in a significant reduction in the commercial aviation accident rate. Also, study of factors affecting HR performance authorities participate in developing systems in order to help operators better manage human error. This paper for the first time presents an intelligent framework based on ANFIS, FDEA and statistical tests for HR performance assessment and analysis with the ability of handling uncertainty and vagueness existing in real world environment.

A Psychophysical Protocol to Develop Ergonomic Recommendations for Sitting and Standing Workstations.

OBJECTIVE: The aim of this study was to determine user self-selected setup for both sitting and standing computer workstations and identify major differences. BACKGROUND: No current ergonomic setup guideline for standing computer workstations is available. METHODS: Twenty adult participants completed four 45-min sessions of simulated office computer work with an adjustable sit-stand computer workstation. Placement and relative position of all workstation components, including a cordless mouse, a cordless keyboard, a height-adjustable desk, and a 22-inch monitor mounted on a mechanical-assisted arm were recorded during the four sessions, which alternated between sitting and standing for each session. Participants were interrupted four times within each session, and the workstation was "reset" to extreme locations. Participants were instructed to adjust the location to achieve the most comfortable arrangement and to make as many adjustments during the session to achieve this goal. RESULTS: Overall, users placed the keyboard closer to their body (sternum), set desk height lower than their elbow, and set the monitor lower relative to their eyes with a greater upward tilt while standing compared to sitting. During the 45-min sessions, the number of adjustments participants made became smaller and over the four sessions was consistent, suggesting the psychophysical protocol was effective and consistent. CONCLUSION: Users preferred different workstation setups for sitting and standing computer workstations. Therefore, future setup guidelines and principles for standing computer workstations may not be simply translated from those for sitting. APPLICATION: These results can serve as the first step toward making recommendations to establish ergonomic guidelines for standing computer workstation arrangement.

Ergonomics standards and guidelines for computer workstation design and the impact on users' health - a review.

This paper presents an overview of global ergonomics standards and guidelines for design of computer workstations, with particular focus on their inconsistency and associated health risk impact. Overall, considerable disagreements were found in the design specifications of computer workstations globally, particularly in relation to the results from previous ergonomics research and the outcomes from current ergonomics standards and guidelines. To cope with the rapid advancement in computer technology, this article provides justifications and suggestions for modifications in the current ergonomics standards and guidelines for the design of computer workstations. Practitioner Summary: A research gap exists in ergonomics standards and guidelines for computer workstations. We explore the validity and generalisability of ergonomics recommendations by comparing previous ergonomics research through to recommendations and outcomes from current ergonomics standards and guidelines.

How Work Organization Affects the Prevalence of WMSDs: A Case-control Study.

OBJECTIVE: In this study, we aimed at exploring the association between work-related musculoskeletal disorders (WMSDs) and work organization based on a case-control study. METHODS: A total of 1938 workers who claimed to suffer from WMSDs were selected from Beijing, Henan, Hubei, and the Guangdong province. The control group consisted of 2009 workers employed in similar industries without severe disease or musculoskeletal discomforts. We used a modified version of the questionnaire developed by the NMQ and the DMQ to investigate individual and work-related factors. RESULTS: A total of 13 variables (P<0.1) were selected by the chi-square test and finally, 7 variables entered into the equation, with 6 variables reaching statistical significance (P<0.05). The odds ratios (OR) of 'work changing with season' and 'sufficient rest time' did not reach 1 (0.749 and 0.441, respectively). In addition, 'sufficient rest time' seemed to be the stronger protective factor according to its higher standardized coefficient. And 'repetitive work every minute', 'constantly repetitive work' (every day), 'shortage of site personnel', and 'often switching shifts with others' seemed to be the risk factors. CONCLUSION: Work organization may have comprehensive effects on the occurrence of WMSDs. This pattern of associations suggests that further investigation into the mechanism of how work organization affects the prevalence of WMSDs is required.

Three-Dimensional Eye Tracking in a Surgical Scenario.

INTRODUCTION: Eye tracking has been widely used in studying the eye behavior of surgeons in the past decade. Most eye-tracking data are reported in a 2-dimensional (2D) fashion, and data for describing surgeons' behaviors on stereoperception are often missed. With the introduction of stereoscopes in laparoscopic procedures, there is an increasing need for studying the depth perception of surgeons under 3D image-guided surgery. METHODS: We developed a new algorithm for the computation of convergence points in stereovision by measuring surgeons' interpupillary distance, the distance to the view target, and the difference between gaze locations of the 2 eyes. To test the feasibility of our new algorithm, we recruited 10 individuals to watch stereograms using binocular disparity and asked them to develop stereoperception using a cross-eyed viewing technique. Participants' eye motions were recorded by the Tobii eye tracker while they performed the trials. Convergence points between normal and stereo-viewing conditions were computed using the developed algorithm. RESULTS: All 10 participants were able to develop stereovision after a short period of training. During stereovision, participants' eye convergence points were 14 ± 1 cm in front of their eyes, which was significantly closer than the convergence points under the normal viewing condition (77 ± 20 cm). CONCLUSION: By applying our method of calculating convergence points using eye tracking, we were able to elicit the eye movement patterns of human operators between the normal and stereovision conditions. Knowledge from this study can be applied to the design of surgical visual systems, with the goal of improving surgical performance and patient safety.