Video Display Terminal Operators Research Articles

Analysis of occupational stress and its correlation with oxidative-antioxidant levels among employees of a power grid enterprise in Guangdong

BackgroundOccupational stress and its health effects on occupational populations have attracted extensive attention from researchers in public health. The stressors faced by employees of power grid enterprises are increasing progressively, which is easy to cause occupational stress. The balance of the body’s oxidative-antioxidant levels plays an essential role in maintaining the body’s health status. This study aims to explore occupational stress and its correlation with oxidative-antioxidant levels in employees of a power grid enterprise.MethodsA cluster random sampling method was used to investigate the basic information of 528 employees in a power grid enterprise and investigate the two occupational stress models of employees by using the Job Content Questionnaire based on the job demand-control-support (JDC) model, and the Effort-Reward Imbalance Questionnaire based on the effort-reward imbalance (ERI) model, respectively. Peripheral blood samples were collected from the employees to measure the levels of malondialdehyde (MDA), total antioxidant capacity (TAC), and superoxide dismutase (SOD). The correlation between different models of occupational stress level and the body’s oxidation-antioxidation level was further explored.ResultsThe detection rate of high JDC model occupational stress was 50.6% and the detection rate of high ERI model occupational stress was 50.9%. The JDC model occupational stress was significantly associated with high-temperature and high-altitude operation, visual display terminal operation, monthly income, and exercise (all P < 0.05). The ERI model occupational stress was significantly associated with visual display terminal operation (all P < 0.05). The results of the generalized additive model showed that SOD levels had a non-linear relationship with the D/C ratio as well as the E/R ratio. With the D/C ratio close to 1, SOD levels raised rapidly. When the E/R ratio exceeded 1, the SOD level raised rapidly (all P<0.05) . TAC levels were negatively associated with the E/R ratio (P < 0.05).ConclusionThe detection rates of occupational stress in both models among employees in a power grid enterprise are higher. ERI model occupational stress was associated with body TAC and SOD levels, and JDC model occupational stress was associated with body SOD levels.

Control of Glare for VDT Operators

The widespread use of video display terminals (VDTs) in offices has been accompanied by many complaints of visual problems. A recent study by the Canadian Labour Congress on vision problems among 2,300 office workers showed that VDT operators report twice as many vision problems and require more frequent changes in lens prescription. Visual complaints have stimulated research into new means of relieving the discomfort experienced by VDT operators.

Control of Glare for VDT Operators

Since the introduction of video display terminals (VDTs) into offices, "glare" has become a source of patient complaints and a major triggering factor of migraine attacks among VDT users. Many patients are bothered by direct glare from fluorescent lamps or reflected glare from the surface of the screen. In order to reduce the impact of glare on VDT operators, some manufacturers have installed anti­glare filters on the screen to reduce the reflective glare. Special luminaires with mirrored louvers directing the luminous flux downwards are recom­mended for lighting systems in VDT areas, but most offices are still illuminated by fluorescent lamp fittings not designed for this type of work.

Effects of anthocyanin, astaxanthin, and lutein on eye functions: a randomized, double-blind, placebo-controlled study.

We examined the effects of a test food containing anthocyanin, astaxanthin, and lutein on the eye function in healthy Japanese adults with eye fatigue after operating visual display terminals. Forty-four subjects were randomly but equally assigned to the active or placebo group. Two active or placebo capsules were taken once daily for 6 weeks. Accommodative function, tear film break-up time, visual acuity, the value of Schirmer’s test, macular pigment optical density level, muscle hardness, and a questionnaire were evaluated before and after a 6-week intervention. Each group included 20 subjects in the efficacy analysis. The active group showed a significant improvement in the percentage of pupillary response of an average of both eyes and dominant eye pre- and post-visual display terminal operation at 6 weeks compared with the placebo group. Moreover, the active group showed a significant improvement in the scores of “A sensation of trouble in focusing the eyes” and “Difficulty in seeing objects in one’s hand and nearby, or fine print” compared with the placebo group between before and after ingestion. Therefore, 6-weeks consumption of the test food inhibited a decrease in the accommodative function caused by visual display terminal operation (UMIN000036989).

Work Ability among Italian Bank Video Display Terminal Operators: Socio-Demographic, Lifestyle, and Occupational Correlates.

Bank employees, especially video display terminal (VDT) operators, are constantly exposed to various occupational risks, such as the adoption of awkward postures, repetitive finger movements, and utilization of software with poor usability, which may lead to computer visual syndrome, tension headache, lower back pain, and/or stress, which compromises their overall health and work ability (WA). Thus, in this cross-sectional study, we aimed to establish that the determinants among socio-demographic, lifestyle, and occupational characteristics are associated with impaired WA in bank VDT operators. To this end, we administered a set of socio-demographic, lifestyle, occupational, and Work Ability Index (WAI) questionnaires to 2077 Italian bank VDT operators. Univariate linear regression models reveal that their mean WAI score is inversely associated with gender, age, dependent family members, and a part-time job, whereas it is directly associated with the educational level and physical activity. In addition, multivariate analysis shows that their mean WAI score is inversely associated with age and a part-time job, but was directly associated with the educational level, the marital status, and physical activity. Overall, VDT operators working in Italian banks display high WA even though this latter tends to decline with aging. In light of the progressive aging of the workforce in Italy, our results provide the rationale for the design of interventions aimed to mitigate the detrimental effects of aging on WA of bank VDT operators.

Analysis on the quality of life and its influencing factors of visual display terminal operators in Internet enterprises

Objective: To investigate the quality of life of the visual display terminal (VDT) operators in Hangzhou Internet enterprises and to analyze its influencing factors. Methods: Through cluster sampling,, 944 employees were investigated by demographic and general health questions and the MOS 36-Item Short Form Health Survey Questionnaire from October to November in 2016 and carried out statistical analysis. Results: VDT operators' physical functioning, role-physical, bodily pain, general health, vitality, social functioning, role-emotional, mental health, physical component summary and mental component summary scores were (86.3±17.0) , (82.5±30.3) , (80.6±16.1) , (56.8±18.6) , (53.7±15.6) , (78.5±17.8) , (81.2±31.9) , (48.8±19.3) , (51.1±8.9) , (43.8±9.1) . Except physical functioning, role-physical and physical component summary scores, the scores of other scales and mental component summary were lower than the norm (P<0.05) . Multivariable logistic regression showed that vegetable intake, sleeping and physical exercise had an impact on the physical component summary score. The influential factors of mental component summary score included marital status, education, neck pain and health concerns. Conclusion: We should pay attention to the quality of life of VDT operators in Internet enterprises, especially their mental health.

Efficacy on visual display terminal syndrome treated with jingjin therapy of Zhuang medicine

To observe the efficacy and explore the effect mechanism on visual display terminal syndrome treated with jingjin therapy of Zhuang medicine. Sixty-five patients of visual fatigue induced by the visual display terminal operation were treated with jingjin trigeminy therapy of Zhuang medicine, e.g. massage manipulation, acupuncture and cupping; acting on the specific stimulating areas in Zhuang medicine, relevant with orbit, temple, forehead, ear and Baihui (GV 20). Each treatment lasted 40 min, once every two or three days. Totally, 10 to 14 treatments were required. The scores of visual symptoms and the ocular hemodynamics before and after treatment were observed, and clinical effect were evaluated in the two groups. After treatment, the scores of visual symptoms were reduced apparently as compared with those before treatment (all P<0.05). The total effective rate was 84.6% (55/65). The peak systolic velocity (PSV), the end diastolic velocity (EDV) in anterior ciliary artery (ACA) and the central retinal artery (CRA) were improved obviously, indicating the significant differences before and after treatment (all P<0.05). The jingjin therapy of Zhuang medicine alleviates the visual symptoms in patients of visual fatigue and improves visual quality. The effects are related to the improvement of ocular microcirculation.

Efficacy of Pressure Biofeedback Guided Deep Cervical Flexor Training on Forward Head Posture in Visual Display Terminal Operators

Efficacy of Pressure Biofeedback Guided Deep Cervical Flexor Training on Forward Head Posture in Visual Display Terminal Operators

Can clinical measures of upper quarter postural muscle performance predict neck pain in visual display terminal operators?

Can clinical measures of upper quarter postural muscle performance predict neck pain in visual display terminal operators?

Meibomian gland dysfunction and ocular discomfort in video display terminal workers

Meibomian gland dysfunction (MGD) is one of the most common ocular disorders encountered in clinical practice. The clinical manifestations of MGD are related to the changes in the tear film and ocular surface with symptoms of ocular discomfort. In recent years, many surveys have evaluated symptoms associated with the use of Video Display Terminals (VDT), and VDT use is recognized as a risk factor for eye discomfort. The aim of the present study was to determine if the presence of MGD contributes to the signs and symptoms of ocular discomfort during the use of VDT. In course of a routine health surveillance programme, a group of 70 subjects fulfilled the inclusion criteria and responded to a questionnaire about symptoms of ocular discomfort. The following ocular tests were performed: tear break-up time, fluorescein corneal stain, and basal tear secretion test. A total of 52 subjects out of 70 (74.3%) had MGD. A statistically significant correlation between the symptoms of ocular discomfort and hours spent on VDT work was observed in the total population (r=0.358; P=0.002; 95% CI 0.13-0.54) and in the group of subjects with MGD (r=0.365; P=0.009; 95% CI 0.103-0.58). Such correlation was not shown in subjects without MGD. The high prevalence of MGD among the subjects with symptoms of ocular discomfort suggests that this diagnosis should be considered when occupational health practitioners encounter ocular complaints among VDT operators. It appears that MGD can contribute to the development of ocular discomfort in VDT operators.

Relationship between occupational stress and blood glucose, blood lipid, blood pressure of video display terminal operators

To explore the relationship between occupational stress and blood glucose, Blood lipid and blood pressure. 108 video display terminals(VDT) operators who had the working experience were recruited to the study. The occupational stress indicator (OSI), the lever of blood glucose, cholesterol, triglyceride, lipoprotein of high density and lipoprotein of low density in serum were measured by using GOD-PAP, CHOD-PAP, GPO-PAP and PVS. The subjects were classified into three groups according to the score of occupational stress. The contents of blood glucose of low, middle and high level of stress groups were (3.39 +/- 1.24), (3.59 +/- 1.26), (2.54 +/- 0.94) mmol/L respectively (F = 7.324, P < 0.01), and with the increase of level of stress, the content of blood glucose decreased significantly (r = -0.376, P < 0.01). The level of blood glucose of VDT operators is affected by occupational stress, among video display terminals and it can be used as the index for estimating occupational stress.

A Comparative Assessment of the Impact of Different Occupations on Workers’ Static Musculoskeletal Fitness

An ergonomic assessment of the involvement of static muscular forces like back strength, grip strength and pinch strength in different occupations was made. A study was conducted on 45 normal adult males (15 subjects per group) which included video display terminal (VDT) operators, industrial workers and safety inspectors. Their maximum back strength, handgrip strength and pinch strength were measured with dynamometers. The observed values of back strength were significantly lower in VDT operators while significantly higher in safety inspectors and moderate in industrial workers. The values of grip strength and pinch strength of all sample groups were more or less similar. The findings clearly indicate that static muscular strength varies significantly in different occupations. Heavy static muscular load might lead to an accumulation of metabolic waste and toxins on the back resulting in lower back strength in VDT operators and industrial workers.

Effectiveness of a new back belt in the maintenance of lumbar lordosis while sitting: a pilot study

This study compared the conditions of no belt and new belt wearing and evaluated the effects of the belt in the maintenance of lumbar lordosis during simulated sitting tasks. Trunk angle and lumbosacral angle were examined under the experimental conditions. Nine subjects performed a data entry task while sitting at a desk during each 60-min experimental period. Results showed that there were significant differences in trunk angle and lumbar posture between the no belt and the new belt condition (with an average difference of −14.1° in lumbar lordosis and 16.9° in trunk angle) during the final 10-min stage of the task. The new belt seemed to provide support for the back by the counter-supporting force from the knees. The results suggest that the new belt may be useful in seated tasks because of its maintenance of lumbar lordosis and erect trunk. Relevance to industry With the expanding use of video display terminals (VDTs), a high incidence of symptoms in VDT operators has been reported. Many studies indicated a higher risk of low back pain (LBP) with work performed in sitting postures. The new belt proposed in this study provides an alternative to the prevention of LBP from the VDT task.

The effect of work-rest schedules and type of task on the discomfort and performance of VDT users

Consideration of the literature survey indicates that video display terminal (VDT) operators tend to have a high incidence of musculoskeletal problems, visual fatigue, and job stress. Although a number of ergonomic improvements in workstation design and work environment can help to reduce these problems, a proper work-rest schedule deserves consideration since it is easily applicable and inexpensive. The objective of this study was to compare the work-rest schedules for VDT operators considering data entry and mental arithmetic tasks. An experiment was conducted with 10 male college students as participants. The methodology included a discomfort questionnaire and performance measures. The independent variables were the work-rest schedule (60-minute work/10-minute rest, 30-minute work/5-minute rest, and 15-minute work/micro breaks) and the type of task (data entry and a mental arithmetic task). The results were analysed using multiple analysis of variance followed by separate analyses. The 15/micro schedule resulted in significantly lower discomfort in the neck, lower back, and chest than the other schedules for data entry task. The 30/5 schedule followed by 15/micro schedule resulted in the lowest eyestrain and blurred vision. Discomfort in the elbow and arm was the lowest with the 15/micro schedule for the mental arithmetic task. The 15/micro schedule resulted in the highest speed, accuracy, and performance for both of the tasks, compared with the 60/10 and 30/5 schedules. The data entry task resulted in significantly increased speed, accuracy, and performance, and lower shoulder and chest discomfort than the mental arithmetic task.

A Strategy to Design a Work-Rest Schedule for VDT Operators Performing Data Entry and Mental Tasks

An experiment was conducted with ten male subjects who performed data entry and mental tasks. Scores of subjective discomfort questionnaire, speed, accuracy, and performance of the subjects and electromyography measurements from trapezius and flexor carpi radialis muscles were recorded. Three different work-rest schedules were applied: 60-minute work/10-minute rest, 30-minute work/5-minute rest, and for the third schedule, the subjects received four breaks from Video Display Terminal (VDT) work each hour additional to a 14-minute break after two hours. Subjects were asked to enter randomly created alphanumeric data (last name, first name, and phone number) for data entry task and to solve randomly created addition and subtraction problems as mental task. Mental task resulted in a higher psychological discomfort, lower physical discomfort, and lower performance than data entry task. The results of the study suggest that the 15/micro schedule is superior to the longer and infrequent rest break schedules considering upper extremity discomfort, eyestrain, speed, accuracy, performance, and the load in trapezius muscle for both data entry and mental tasks.

Luminance of the Surround and Visual Fatigue of VDT Operators

Luminance distribution in the visual field is considered as one of causal factors with a significant influence on visual fatigue, especially for intensive and extended Video Display Terminal (VDT) work. The aim of the study was to define visual fatigue of VDT operators for different values of surrounding luminance. Experiments were carried out in laboratory conditions under 3 lighting conditions. Only 1 lighting parameter—the luminance of the wall behind the display (surrounding luminance)—changed. Visual fatigue was measured both by a subjective evaluation of different visual complaints (asthenopic symptoms) and by objective measurements of changes in the following visual functions: accommodation, convergence, habitual horizontal phoria, critical fusional frequency (CFF), and visual acuity. The same experiments were done for CRT (Cathode Ray Tube) and LCD TFT (Liquid Crystal Display with Thin Film Transistor) screens. The results of the study have shown that there was no significant influence of the value of surrounding luminance on the asthenopic symptoms for either type of screen. A general tendency towards bigger visual complaints for LCD TFT than for CRT participants was found. An objective evaluation of visual fatigue demonstrated a tendency towards bigger changes in visual functions with an increase of surrounding luminance for both screens. Statistical analysis of the results has shown that surrounding luminance influences significantly the reduction of the accommodation amplitude (significance level < .05).

Predictive models of carpal tunnel syndrome causation among VDT operators

Carpal tunnel syndrome (CTS), a cumulative trauma disorder of the hand and wrist, is one of the most common disabling injuries experienced by video-display terminal (VDT) operators. The purpose of this study was to develop a theoretically based operational quantitative predictive model of the risk of work-related CTS among VDT operators. A total of 100 female VDT operators, who performed a variety of office functions, were studied at a major midwestern university. Data were collected on job exposure, anthropometry and posture factors using questionnaires, direct observation and video-recording. Discriminant analysis and logistic regression were performed to develop the operational models. The results of the study indicated the following: (1) percentage of workday working with a VDT was the most significant factor and accounted for 60% of the variance explaining the causation of musculoskeletal discomforts associated with CTS; (2) discriminant function with six variables (i.e. work duration, trunk incline, wrist extension, wrist ulnar deviation, overall anthropometric measure, weighted anthropometric measure) correctly classified 73% of the CTS group and 72% of the non-CTS group; (3) using the logistic regression model, the probabilities associated with changes in the predictive variables as affecting CTS risk are presented such that increasing the daily work duration from 1 h to 4 h increases the probability of CTS risk from 0.45 to 0.92. The results of the study suggest that the main causation of CTS is job design, the secondary (and lesser cause) is posture associated with the workplace design and the least contributing factor to CTS causation is the individual's anthropometric make-up.

Measurement variability in upper extremity posture among VDT users

Hand and arm posture while keying is frequently mentioned as a risk factor for upper extremity musculoskeletal disorders (UEMSDs) among video display terminal (VDT) operators. However, many epidemiologic studies have not included measures of posture of VDT operators, in part, because of the difficulty of assessing posture rapidly and reliably among large numbers of subjects. For a single measure of posture to be useful for estimating dose-response relationships between posture and risk of UEMSDs, the within-subject variability of the postural measure must be smaller than the between-subject variability of the postural measure. In addition, the measure must be stable over time. We estimate the ratio of between- to within-subject variability for manual goniometry by measuring six postural angles on six occasions among 19 subjects using VDTs. For each postural angle, between-subject variability was substantially and statistically significantly larger than within-subject variability. Stability of postural measures over time was sufficient to justify a single postural measurement in epidemiologic studies. We conclude that manual goniometry can provide useful information about upper extremity posture among VDT users for use in epidemiologic studies of UEMSDs.

Wrist postures in video display terminal operators (VDT) using different keyboards

This study examined the differences in wrist motion using three types of keyboards: a standard QWERTY design and two alternative designs, the Truform Ergonomic keyboard and the Health Care Comfort keyboard. The Comfort keyboard (adjusted at a lateral slope of 30° and horizontal split of 20° and the Truform keyboard (with a 20° horizontal split) were compared with the standard flat QWERTY keyboard. Twenty adult video display terminal (VDT) workers from the Boston area ranging from 22 to 68 years of age volunteered to participate in this study. In randomly assigned sequences, participants typed for 5 min on each keyboard while their wrist motions were measured using the WristSystem by Greenleaf Medical Systems, Inc. Contrast score analysis was used to analyze mean values in flexion-extension and radial-ulnar deviation of the right and left hands between the three sessions. The alternative keyboards significantly reduced ulnar deviation (left: t(19) = 3.46, P < 0.0025; right: t(19) = 5.83, P < 0.00001), and extension (left: t(19) = 2.82, P < 0.001; right: t(19) = 3.99, P < 0.0005). Results suggest that the Comfort keyboard yielded less ulnar deviation and extension as compared to the standard QWERTY keyboard (Left Extension: QWERTY mean = 21.45, Comfort mean = 18.67; Right Extension: QWERTY mean = 22.9, Comfort mean = 14.45; Left Ulnar Deviation: QWERTY mean = 14.54, Comfort mean = 7.44; Right Ulnar Deviation: QWERTY mean = 17.1, Comfort mean = 6.12). Although the Truform keyboard reduced ulnar deviation (Left: QWERTY mean = 14.54, Truform mean = 9.42; Right: QWERTY mean = 17.1, Truform mean = 9.67), it also yielded extension values comparable to those using the QWERTY (Left Extension: QWERTY mean = 21.45, Truform mean = 24.66; Right Extension: QWERTY mean = 22.9; Truform mean = 22.4). Both alternative designs yielded slightly higher values for radial deviation (left: t(19)=-2.4, P > 0.25; right: t(19)=-3.75, P > 0.25) and flexion (left: t(19)=-1.39, P > 0.25; right: t(19)=-3.75, P > 0.25). Still, these increases remained well within the 'neutral' zone (< 15-20°). The results suggest that among the three keyboard designs, the Comfort keyboard was the most effective in maintaining a neutral wrist posture. Although the Truform significantly reduced ulnar devation, it also yielded extension values beyond the neutral range (> 15°). Clinically, these findings may assist occupational therapists in suggesting appropriate keyboard designs during workstation ergonomic modification or consultation. Further research is needed to reinforce these findings.

Comparisons of wrist postures in VDT operators using wrist rests and forearm supports

The purpose of this study was to examine wrist motions in video display terminal (VDT) workers using the Greenleaf Medical WristSystem. This study was developed because of the limited research about the effectiveness of ergonomic equipment for VDT operators, as well as the recent increase in cumulative trauma disorders (CTDs) among these workers. Twenty adult VDT operators with no history of CTD were recruited from Boston University and surrounding businesses. WristSensorTM gloves containing dual-axis sensors for detection of dynamic wrist movements were worn by participants. Calibrations were then performed through the Movement Analysis System (MAS) software, after which participants were requested to type using a wrist rest (condition A), using forearm supports (condition B), using the wrist rest and forearm supports together (condition C), and finally using no form of wrist or forearm support (condition D). It was assumed by the investigators that wrist extension and ulnar deviation would decrease when using the wrist rest or forearm support, with the greatest change occurring when using both types of support. Questionnaires requesting demographic information were completed by each participant. Contrast scores were also calculated and converted into t -tests and their corresponding P -values. The average degrees of motion for both right and left hands were: flexion 4.5°, extension 18.9°, ulnar deviation 15.3°, and radial deviation 2.0°. P-values for all four conditions in the left hand were found to be significant and are as follows: extension t(19) = 2.35, P < 0.025, flexion t(19) = 2.17, P < 0.025, ulnar deviation t(19) = 3.41, P < 0.0025, and radial deviation t(19) = 2.5, P < 0.025. The only significant P-value in the right hand was during ulnar deviation: t(19) = 2.7, P < 0.01. Research suggests that wrist extension greater than 15° and ulnar deviation greater than 20° can be predisposing factors to the development of CTDs. In this study, all four wrist motions remained under 20° during the three conditions using the wrist rest and forearm supports. A trend of continued decreases in ulnar deviation and wrist extension from using no supports to that requiring both types of supports was also observed. Specifically, the smallest degree of wrist extension appeared when participants used only the wrist rest; ulnar deviation was smallest when both supports were used. Right hand degree values were found to be generally larger than those for the left hand. It is hoped that these results can serve as a foundation for future investigation into the effectiveness of wrist and forearm supports in reducing CTDs.