An Examination of the Relationship between Visual Fatigue Symptoms with Flicker Value Variations in Video Display Terminal Users

In most sensitive occupations such as nuclear, military and chemical industries closed circuit systems and visual display terminals (VDTs) are used to carefully control and assess sensitive processes. Visual fatigue is one of the factors decreasing accuracy and concentration in operators causing faulty perception. This study aimed to find out a relationship between visual fatigue symptoms (VFS) of Flicker value variations in video display terminal (VDT) operators. This cross-sectional study, conducted in 2011, aimed to examine visual fatigue and determine the relationship between its symptoms and visual flicker value changes in 248 operators of VDTs in several occupations. The materials used in this study were a visual fatigue questionnaire of VDTs and a VFM-90.1 device. Visual fatigue was measured in two stages (prior to beginning to work and 60 min later). The data were analyzed by SPSS11.5, using descriptive statistics, paired t-test, simple and multiple linear regressions, correlation and recognition coefficients. Then regression equations of changes in flicker value depending on the changes in the main domains and the changes in final score before the questionnaire were obtained. Paired t-test indicated significant differences in the mean score of visual fatigue symptoms and the mean score of flicker value between the two stages, respectively (P ≤ 0.001). Simple and multiple regressions of flicker value variations, for the last visual fatigue changes in questionnaire score and the four main domains of the questionnaire were obtained R2 = 0.851 and R2 = 0.853, respectively. Correlation coefficient in the above tests indicated reverse and significant relationships among flicker value changes with changes in questionnaire score and visual fatigue symptoms. Diagnosing the first symptoms of visual fatigue could be an appropriate warning for VDTs operators in sensitive occupations to react suitably, in behavior and management, to control or treat visual fatigue and prevent errors efficiently

The effect of cushion of air on vibration transmitted to vehicle drivers based on standard

زمینه و هدف: ارتعاش تمام بدن (WBV) از دلایل اصلی اختلالات اسکلتی عضلانی رانندگان است. یک روش برای کاهش ارتعاش استفاده از وسیله عایق می باشد. در این تحقیق، جهت کاهش میزان ارتعاش از یک تشکچه هوا استفاده شده و با اندازه گیری ارتعاش منتقله به رانندگان قبل و بعد از استفاده از تشکچه، اثربخشی آن در کنترل ارتعاش مورد بررسی قرار گرفت. روش بررسی: این مطالعه، مداخله ای و بر روی 95 نفر از رانندگان شرکت واحد اتوبوسرانی انجام شد. پارامترهای ارتعاش در سه محور ورود ارتعاش به بدن، در دو مرحله قبل و بعد از قرار دادن تشکچه بر روی صندلی راننده توسط دستگاه ارتعاش سنج اندازه گیری و با استفاده از آزمون آماری t زوجی مقایسه شدند. یافته ها: مقایسه مقادیر ارتعاش قبل و بعد از استفاده تشکچه نشان داد که ماکزیمم فشار (Pmax) در محورهای X،Y به ترتیب(m/s2) 2921/0 و (m/s2) 3081/0 کاهش (05/0

An examination of association of visual fatigue symptoms with flicker value changes in video display terminal operators

Background and aims: In the majority of sensitive occupations, such as nuclear, military, chemical, etc, closed circuit systems and visual display terminals (VDTs) are used to control and monitor sensitive processes. Visual fatigue is one of the factors that decreases operators’ precision and awareness and makes the reception of visual data from VDT erroneous. This study was aimed to exanimate the association of visual fatigue symptoms with flicker value changes in video display terminal operators. Methods: This cross-sectional study aimed to examine visual fatigue and to determine the association between its symptoms and visual flicker value changes in 248 operators of VDTs in several occupations was conducted in 2011. The instruments that have been used in this study were a visual fatigue questionnaire of VDTs and a VFM-90.1 device. Visual fatigue was measured in two stages (prior to beginning to work and 60 min later). The data were analyzed using SPSS, descriptive statistics, paired t-test, simple and multivariate linear regression, Pearson correlation, recognition coefficient (R2) and regression equations of changes in flicker value depending on changes in the main domains and changes in final score for the questionnaire were obtained. Results: Paired t-test indicated significant differences in the mean score of visual fatigue symptoms and the mean score of flicker value between two stages respectively (P< 0.001). Simple and multivariate regressions were obtained, respectively for the last visual fatigue changes in questionnaire score (R2 = 0.923) and the four main domains of the questionnaire (R2= 0.924). Correlation coefficient in the above testes indicated on inverse and significant association of flicker value changes with changes in questionnaire score and visual fatigue symptoms. Conclusion: diagnosing the first symptoms of visual fatigue could be an appropriate warning for VDT operators in sensitive occupations to react suitably, in behavior and management, to control or treat visual fatigue and prevent errors efficiently

The Effects of Maximum Aerobic Capacity and Ratings of Perceived Exertion on Muscular Strength and Endurance

Grip and pinch strength are the most important factors affecting the hand’s performance. This study aimed to evaluate the relationship among maximum aerobic capacity (Vo2max) and ratings of perceived exertion (RPE) with grip and pinch strength and endurance and their impact on these factors. This cross-sectional study was performed among 83 male students and office workers by means of simple random sampling. To assess the Vo2max, RPE, grip and pinch strength and endurance the Step Test, Borg scale, dynamometer and pinch gauge were used, respectively. The findings of the study indicate that there is a direct relationship between the Vo2max with grip strength and endurance, pinch strength and endurance and BMI. On the other hand, there is an indirect relationship between RPE with grip and pinch strength and Vo2max. Moreover, there was no relationship between RPE with grip and pinch endurance. It was also found that there is a direct relationship between the BMI with grip and pinch strength, pinch endurance, and Vo2max. Finally, no relationship was observed between BMI and grip endurance. Moreover, the Vo2max was found to have no influence on the grip and pinch strength and pinch endurance, but it has an influence on the grip endurance. In jobs that require high grip and pinch strength and endurance employed those with high Vo2max so that work-related musculoskeletal disorders (WMSDs) would be prevented

The Relationship between Physical Activity and Body Mass Index with Reaction Time in the University Administrative Staff

Background: Today, physical activity as an important topic in physiology has attracted the attention of many researchers. The reaction time (simple, diagnostic and selective) which depends on the time of stimulation of sensory receptors, is an important factor in many movement functions. In this study, the authors attempted to evaluate the relation between physical activity and reaction time in adults. Methods: This cross-sectional study was carried out on 82 male administrative staff using simple random sampling. The Iranian version of the International Physical Activity Questionnaire (IPAQ) and a Reaction Timer were used to determine physical activity and reaction time, respectively. Data analysis was carried out by SPSS 20 and Pearson correlation coefficient. Results: There was a significant relation between reaction times and physical activity with age (P<0.05), while there was no significant relation between selective reaction time and physical activity with work experience. Also, there was a significant correlation between simple reaction time and physical activity with body mass index (BMI) (P<0.05), but no significant correlation was found between diagnostic and selective reaction time with BMI. Moreover, a significant relation was found between the types of reaction times and physical activity (P<0.05). Conclusion: According to the results, by increased physical activity the reaction time decreases. So, for employees whose jobs require rapid reaction and high precision, increasing physical activity for reducing the reaction time, and ultimately improving the job performance is recommended. Keywords: Physical Activity, Reaction Time, BMI, Administrative Staf

Evaluation of Musculoskeletal Disorders among computer Users in Isfahan

Along with widespread use of computers, work-related musculoskeletal disorders (MSDs) have become the most prevalent ergonomic problems in computer users. With evaluating musculoskeletal disorders among Computer Users can intervent a action to reduce musculoskeletal disorders carried out. The aim of the present study was to Assessment of Musculoskeletal Disorders among Computer Users in Isfahan University with Rapid Office Strain Assessment (ROSA) method and Nordic questionnaire. This cross-sectional study was conducted on 96 computer users in Isfahan university. The data were analyzed using correlation and line regression by test spss 20. and descriptive statistics and Anova test. Data collection tool was Nordic questionnaire and Rapid Office Strain Assessment method checklist. The results of Nordic questionnaire showed that prevalence of musculoskeletal disorders in computer users were in the shoulder (62.1%), neck (54.9%) and back (53.1%) respectively more than in other parts of the body. Based on the level of risk of ROSA were 19 individuals in an area of low risk, 50 individual area of notification and 27 individual in the area hazard and need for ergonomics interventions. Musculoskeletal disorders prevalence were in women more than men. Also Anova test showed that there is a direct and significant correlation between age and work experience with a final score ROSA (

The relation between the Rating of Perceived Exertion (RPE) and Handgrip Strength among female students in Isfahan University of Medical Sciences

Background: RPE scale can be used for self-assessing worker’s abilities in the workplace. When participants perform a task which transcends their ability, or the grip strength is not appropriate, they experience muscular tension and fatigue. Hand grip is a factor used for preventing muscular skeletal disorders in the upper limb. This study aimed to evaluate the relation between RPE and handgrip strength in female students. Methods: This cross-sectional study was performed among 82 young female students enrolled using simple random sampling. The Borg Scale, a dynamometer, pinch gauge, and treadmill were used to assess the RPE, grip strength, pinch strength, and workload, respectively. Participant’s grip endurance was specified through determining the maximum time (in seconds) that she could continue applying one-third of the maximum voluntary contraction. Data analysis was carried out by SPSS 20, and using Pearson and Spearman correlation coefficients. Results: The findings indicated that there was an inverse relation between RPE with grip (P = 0.011), pinch strength (P= 0.020) and age (P=0.005). Moreover, there was a direct relation between the RPE and heart rate (P=0.048). But, no significant relation was observed between the RPE with grip and pinch endurance, height, or BMI. Conclusion: Based on the results, in jobs that require high grip and pinch strength, people with low RPE should be employed to reduce fatigue and muscular discomfort and improve healt

Investigation Effect of Biorhythm on Work-Related Accidents in The Metal Industry (A Short Report)

Biorhythm is one of the newest subjects in the field of cognition of mental ergonomics which can be very effective in reduction of work-related accidents or mistakes with no apparent reason. With evaluating Biorhythm individuals can intervention action to reduce job accidents carried out. Thus, the aim of this study was to determine the relationship Biorhythm and work-related accidents in the metal industry. This research is a cross-sectional and analytical-descriptive in the metal industrial Isfahan city of 120 work-related accidents during 2015. The required information was collected from available documents in HSE unit of the company biorhythm charts were drawn based on a date of accidents and participants birthdays, using natural Biorhythm Software V3.02 Conduct. Finally، the data were analyzed using spss version 20 and descriptive statistics.This study showed that the frequency of accidents in critical days and negative section of physical cycle was more than expected. Also the frequency of accidents in critical days and negative section of emotional and intellectual cycles was less than expected. Most type of injury, including cuts to 35.8 percent and the lowest type of injury was torsion with 5 percent. Most limb injury, hands and fingers with 51.7 percent and the lowest limb injury were back at 2.5 percent. Accidents outbreak in physical cycles was 38.3 percent. These 120 accidents in additionally were causing 120 loss of working days in effect accident. Most percent of loss of working days were for 20 to 30 days with of 39.2 percent. Most percent of loss of working days were for 20 to 30 days with of 39.2 percent. Due to the physical nature of the work activities in the metal industry can be stated that the study showed that in physical work activities, frequency of accidents in critical days and negative section of physical cycle in which the person is not physically ready to do the job was more than expected. Therefore, by training and increasing the knowledge of workers regarding biological cycle and its effects on mental, emotional and physical status, each person effects can make some changes to their work plans during days that they do not feel well, physically or mentally, in order to prevent the likely accidents

Investigation Effect of Shift Work on Job Burnout and Depression, Anxiety, Stress Scale in Military Personnel

Shift work has been recognized as an important tool for organizing of work in developing countries. The disturbed depression, stress accident are the most common health‐related effects of shift work. The military personnel shift worker during work, are exposed to stress and psychological pressure that certainly affect the efficiency of their work. The aim of this study was to Investigation Effect of shift work on job burnout and Depression, Anxiety, Stress Scale in military personnel. This cross-sectional study was carried out on 100 military personnel male in Southern Iran. Respondents were divided into two groups based on their working schedule (50 shift work personnel / 50 day work personnel). Data collection tools were a Depression, Anxiety, and Stress Scale (DASS-21), demographic characteristics and Maslach job burnout questionnaire. Convenience sampling was used as sampling method. Finally, Data analysis was performed with SPSS (version 20), descriptive statistics, One Way Anova test, ANCOVA and t-independent test. The results of showed that shift work has an impact on burnout and DASS-21 and mean obtained score for DASS-21 and job burnout in shift workers are more day work individuals. Analysis of variance test showed significant difference between job burnout in day workers and shift workers and job burnout were more in shift workers. Also significant difference between DASS-21 in day workers and shift workers and DASS-21 was more in shift workers. This study showed that shift work has an impact on burnout and scale DASS-21 shall is taken to Intervention actions in shift works

Designing and validation a visual fatigue questionnaire for video display terminals operators

Background: Along with the rapid growth of technology its related tools such as computer, monitors and video display terminals (VDTs) grow as well. Based on the studies, the most common complaint reported is of the VDT users. Methods: This study attempts to design a proper tool to assess the visual fatigue of the VDT users. First draft of the questionnaire was prepared after a thorough study on the books, papers and similar questionnaires. The validity and reliability of the questionnaire was confirmed using the content validity index (CVI) beside that of the Cronbach's Coefficient Alpha. Then, a cross-sectional study was carried out on 248 of the VDT users in different professions. A theoretical model with four categories of symptoms of visual fatigue was derived from the previous studies and questionnaires. Having used the AMOS16 software, the construct validity of the questionnaire was evaluated using the confirmatory factor analysis. The correlation co-efficiency of the internal domains was calculated using the SPSS 11.5 software. To assess the quality check index and determining the visual fatigue levels, visual fatigue of the VDT users was measured by the questionnaire and visual fatigue meter (VFM) device. Cut-off points were identified by receiver operating characteristic curves. Results: CVI and reliability co-efficiency were both equal to 0.75. Model fit indices including root mean of squared error approximation, goodness of fit index and adjusted goodness of fit index were obtained 0.026, 0.96 and 0.92 respectfully. The correlation between the results measured with the questionnaire and VFM-90.1 device was-0.87. Cut-off points of the questionnaire were 0.65, 2.36 and 3.88. The confirmed questionnaire consists of four main areas: Eye strain (4 questions), visual impairment (5 questions) and the surface impairment of the eye (3 questions) and the out of eye problems (3 questions). Conclusions: The visual fatigue questionnaire contains 15 questions and has a very remarkable validity and reliability. Usingthis questionnaire and its findings, one will be able to identify, assess and finally prevent the effective factors of VDT users' visual fatigue