Display Terminal Work Research Articles

Working Psychosocial Conditions and Health Effects for Video Display Terminals Users in Some Administrative Activities

Abstract Working with video display terminals (VDTs) involves different risk factors, including psychosocial risks, that have been recognized as important causes to employees’ health problems (both mental and physical). This is why one of the employers responsibilities is to change work conditions in order to improve the occupational psychosocial environment of all employees and VDT users as well. This paper aimed to explore how psychosocial and ergonomics aspects of VDT work tasks are related to work related health problems, especially to occupational stress symptoms, as perceived by the employees.

Influence of video display terminal use and meibomian gland dysfunction on the ocular surface and tear neuromediators.

To evaluate the effects of video display terminal (VDT) work and meibomian gland dysfunction (MGD) on ocular surface parameters, tear cytokine and substance P (SP) levels, and their association with dry eye disease (DED). This cross-sectional study included 60 patients with evaporative DED and 20 healthy individuals. The DED patients were divided into three groups according to daily VDT work time and presence of MGD. The ocular surface and tear film were assessed using the Ocular Surface Disease Index questionnaire (OSDI), tear film break-up time (TBUT), ocular surface staining, Schirmer II test, and corneal sensitivity. MGD was evaluated with meibography. Corneal nerve alterations were evaluated using in vivo confocal microscopy (IVCM). The tear levels of 30 cytokines and SP were examined. Compared to controls, DED patients had higher OSDI score (p < 0.001), increased corneal staining with fluorescein and lissamine green (p = 0.046, p = 0,038), and lower TBUT (p < 0.001). Tear interleukin-6 levels were higher in DED patients, while tear SP levels did not differ between the groups (p = 0.265). VDT work time showed a weak positive correlation with OSDI (r = 0.274, p = 0.014) and SP level (r = 0.284, p = 0.011). The results of this study show that VDT use and MGD have an adverse effect on the ocular surface. It was also observed that the combination of VDT use and MGD did not significantly increase the ocular surface disease, but longer VDT exposure may be associated with more complaints of ocular discomfort.

Five-year Survey of Personal Computer Work by the Staff of a Teacher Training University and Affiliated Schools

Objective: Occupational research relevant to visual display terminal (VDT) work is expanding on a global scale. To date, examination of possible occupational health-related issues has been insufficient. Methods: We conducted a longitudinal survey (2007-2011) at a teacher training university, investigating various kinds of problematic VDT work, revealing the relationships between occupational and environmental factors (work content, workplace, and working posture) and ocular and musculoskeletal symptoms. Results: Whereas symptoms varied somewhat for men and women who were VDT users, “stooping posture” and “work time (≥ 6 hours)” were the causes of symptoms of “eye fatigue” for both sexes. We identified numerous other sex-specific symptoms as well. Conclusions: These results contribute to improvement of teachers’ occupational and environmental health and offer direction for pre-work education.

Prevalence of Computer Vision Syndrome and Its Relationship with Ergonomic and Individual Factors in Presbyopic VDT Workers Using Progressive Addition Lenses.

This cross-sectional study estimated computer vision syndrome (CVS) prevalence and analysed its relationship with video display terminal (VDT) exposure, as well as sociodemographic, refractive, environmental, and ergonomic characteristics in 109 presbyopic VDT workers wearing progressive addition lenses (PALs). Usual spectacles were measured with a lens analyser, and subjective refraction was performed by an optometrist. CVS was measured with the CVS-Q©. VDT exposure was collected. Ergonomic evaluations were conducted in a normal working posture looking at the screen. Air temperature and relative humidity were measured (thermohygrometer), and illumination was measured (luxmeter). Descriptive analysis and differences in CVS prevalence, as a function of the explanatory variables, were performed (chi-square test). Multivariate logistic regression was used to identify factors associated with CVS (OR and 95% CI). The mean age was 54.0 ± 4.8 years, and 43.1% were women. The mean hours of VDT use at work was 6.5 ± 1.3 hours/day. The prevalence of CVS was 74.3%. CVS was significantly associated with women (OR 3.40; 95% CI, 1.12–10.33), non-neutral neck posture (OR 3.27; 95% CI, 1.03–10.41) and altered workplace lighting (OR 3.64; 95% CI, 1.22–10.81). Providing training and information to workers regarding the importance of adequate lighting and ergonomic postures during VDT use is advised to decrease CVS and increase workplace quality of life.

Approach to Dry Eye in Video Display Terminal Workers (Basic Science).

The use of video display terminals (VDT) and staring at screens of technologic devices, including desktops, laptops, tablets, and smartphones have become ubiquitous in a wide range of age groups because of the rapid advance of network culture-mediated communications. The incidence of dry eye is particularly high in workers that work with VDT. To facilitate an understanding of the mechanisms of VDT-associated dry eye, as well as to develop novel treatment approaches, a VDT worker dry eye model was created. The procedure involved placing rats on a swing in combination with exposure to an evaporative environment. This animal model reveals that the blink frequency was reduced to one-third of the nonswing riding levels, which is similar to the results that have been reported by VDT users. Pathologic analysis of the lacrimal gland in this dry eye model showed that the decrease in tear secretion was accompanied by a decrease in the acinar cell number, and an enlargement of acinar cells was accompanied by filling with an increased volume of secretory vesicles and a loss of intracellular cell structure, suggesting the involvement of lacrimal hypofunction. An interventional study using this dry eye model showed that oral supplementation of some natural ingredients is a possible therapy for relieving symptoms of VDT-associated dry eye. Further investigations for the establishment of VDT use-associated dry eye models that may be used to evaluate ocular discomfort that mimic the condition in humans are needed to understand and modify this type of dry eye.

NGF and iNOS Changes in Tears from Video Display Terminal Workers

ABSTRACTPurpose: To investigate Nerve Growth Factor (NGF) and nitric oxide synthase (iNOS) levels in tears obtained from Video Display Terminal (VDT) workers and correlate their expression with ocular signs and symptoms.Methods: A total of 120 VDT workers (62M/58F; 31–63 years old) and 40 age/sex matched no-VDT volunteers (19M/21F; 30–60 years old) were enrolled in the study. Participants completed the OSDI questionnaire and were subjected to clinical assessment of ocular surface status, including ocular symptoms and tear film parameters. NGF and iNOS levels were quantified in tear samples and their expressions correlated with OSDI, ocular symptoms and tear film parameters.Results: 59.17% of the studied population was symptomatic based on OSDI scores. Women were more commonly affected. The most frequent symptom was asthenopia and except for dryness, no differences were found between genders regarding other symptoms. A statistically significant decrease in NGF levels was found between normal and moderate (p < 0.05) and between mild and moderate (p < 0.05) OSDI grading. iNOS expression was increased in moderate OSDI grading compared to normals (p < 0.05). A negative correlation was found between NGF and respectively OSDI results, dryness and blurry vision (p < 0.05). No correlations were found among NGF, iNOS and ocular surface parameters (Schirmer, BUT, ocular surface staining).Conclusion: Our data suggest that NGF and iNOS levels contribute to VDT ocular discomfort. Further studies are required to better understand the relationship between NGF and iNOS in VDT ocular surface.

Risk Factor, Job Stress and Quality of Life in Workers With Lower Extremity Pain Who Use Video Display Terminals.

ObjectiveTo investigate the general characteristics of video display terminal (VDT) workers with lower extremity pain, to identify the risk factors of work-related lower extremity pain, and to examine the relationship between work stress and health-related quality of life.MethodsA questionnaire about the general characteristics of the survey group and the musculoskeletal symptom was used. A questionnaire about job stress used the Korean Occupational Stress Scale and medical outcome study 36-item Short Form Health Survey (SF-36) to assess health-related quality of life.ResultsThere were 1,711 subjects in the lower extremity group and 2,208 subjects in the control group. Age, sex, hobbies, and feeling of loading affected lower extremity pain as determined in a crossover analysis of all variables with and without lower extremity pain. There were no statistically significant difference between the two groups in terms of job stress and SF-36 values of the pain and control groups.ConclusionJob stress in VDT workers was higher than average, and the quality of life decreased as the stress increased. Factors such as younger age, women, hobbies other than exercise, and feeling of loading influenced lower extremity pain of workers. Further long-term follow-up and supplementary studies are needed to identify risk factors for future lower extremity pain, taking into account ergonomic factors such as worker's posture.

Effects of Perilla frutescens var. acuta Aqueous Extract on the Visual Function

Purpose: To evaluate the effects of Perilla frutescens var. acuta aqueous extract (PFA) on the visual function. Methods: The experiments included 30 male and female with no eye disease and systemic diseases and over –3.00 D of spherical equivalent refractive error. Each Subject took PFA or placebo as a control group. After 2 hours later, they were directed to perform visual display terminal (VDT) work with a smartphone for 2 hours. The visual function(near point of convergence, accommodative force, accommodative facility) was analyzed before and after taking the extract and placebo. Result: As a result of comparing the mean of near point of convergence, it decreased significantly by -0.86 ± 0.16 cm in the PFA group, and increased by +1.23±0.75 cm when the placebo was applied. When comparing the mean accommodative force, it increased significantly by +1.80±2.66 D in the right eye, +1.58±2.54 D in the left eye, +1.83±2.53 D in both eyes when the extract was applied, and decreased significantly by -0.78±2.27 D in the right eye, -1.27±2.04 D in the left eye, -0.84±1.30 D in both eyes when the placebo was applied. In the mean of binocular accommodative facility, only when taking PFA showed a statistically significant change to +1.27±2.41 cpm. Conclusion: In the study, it showed significant effects on controlling the growth of near point of convergence, and increasing accommodative force and binocular accommodative by helping the ciliary muscles to be relaxed and contracted. It would be thought that PFA was engaged in the accommodation and helped to perform the accommodation.

Comparison of The VDT Occupation and VDT-related Hobby Groups in terms of Patients’Subjective Symptoms of VDT Syndrome

The purpose of this study was to investigate the health conditions of occupation group and hobby group related to visual display terminal (VDT) syndrome. The VDT occupation group was mainly composed of the worker in banks, telephone companies, and general offices. The VDT-related hobby group was composed of high school students, and Internet cafe users. A questionnaire survey was conducted to classify the subjects according to hours of computer usage. The results indicated that the occupation group represented a higher level of subjective symptoms than VDT-related hobby group. In the VDT occupation group, ‘Poor body condition’, ‘Feeling uncomfortable or pain in the neck’‘, Feeling uncomfortable or pain in the back’‘, Feeling stressed out’, and‘ Feeling uncomfortable or pain in the shoulder’ items indicated a high level of subjective symptoms. In the VDT-related hobby group, ‘Feeling uncomfortable or pain in the neck’, and‘ Feeling uncomfortable or pain in the back’ items indicated a high level of subjective symptoms. According to the hours of computer usage, 4-6 hours and 6 hours or more groups represented a higher level of subjective symptoms than 2-4 hours group. These findings suggest that Visual display terminal (VDT) work effects the individual's health conditions.

Logistic regression analysis differentiates high from low computer users by facial skin conditions in a population of Chinese women

In the past few decades, video display terminals (VDTs) and computer use have been associated with various skin symptoms in several published reports. In addition, internet beauty sites report that extended computer use leads to acne or accelerated facial aging. For example, the term “computer face” is used to describe premature aging caused by sitting for long periods of time in front of the screen (http://www.marieclaire.com/beauty/news/a12937/computer-screen-skin-problems/). We wished to determine, using instrumental and expert assessment, if prolonged/extended computer use could be associated with certain skin conditions. This study focused on long-term (10 years or more) office VDT work and was designed to include a wide range of confounding variables. One hundred Chinese women were recruited, 50 in each of two groups characterized as either (a) computer users with 8 or more hours per day, or (b) non-users who use computers 1 h or less per day. All subjects lived in Guangzhou and worked in the same building. Confounders were assessed by survey, and included age, smoking, sun exposure history, exercise, and other factors. Skin conditions, which included acne, sebum, wrinkles, and pigment spots, were assessed by instrumental measurements and blinded dermatologist assessment. Age and skin conditions were subjected to logistic regression analysis to determine major contributors which could separate, or distinguish, the computer group from the non-computer group. From this analysis, the office computer users were found to be statistically significantly associated with a higher incidence of acne, higher sebum levels, and a higher risk of self-reported sensitive skin when compared with the non-computer group. The final model suggests that the major contributors in separating the two groups are acne and pigmented spots (UV and brown). These results indicate that facial skin of women within the Chinese population who use computers for 8 h or more a day may be at higher risk for acne; however, they had lower levels of attributes associated with photoaging, such as lentigines and facial wrinkles. Separate pairwise assessment of other variables such as lifetime cumulative sun exposure, sleep quality, smoking behavior, exercise, and cosmetic product use or procedures showed no significant differences between the two groups. This indicates that the results obtained from objective and subjective measurements were not biased due to these potential confounders, but does not reveal the mechanism for the observed differences in skin conditions between computer/VDT users and non-users.

Change in Musculoskeletal Pain in Patients With Work-Related Musculoskeletal Disorder After Tailored Rehabilitation Education: A One-Year Follow-Up Survey.

ObjectiveTo apply tailored rehabilitation education to video display terminal (VDT) workers with musculoskeletal pain and to assess changes in musculoskeletal pain after rehabilitation education.MethodsA total of 8,828 VDT workers were screened for musculoskeletal disorders using a self-report questionnaire. Six hundred twenty-six VDT workers selected based on their questionnaires were enrolled in musculoskeletal rehabilitation education, which consisted of education on VDT syndrome and confirmed diseases, exercise therapy including self-stretching and strengthening, and posture correction. One year later, a follow-up screening survey was performed on 316 VDT workers, and the results were compared with the previous data.ResultsCompared with the initial survey, pain intensity was significantly decreased in the neck area; pain duration and frequency were significantly decreased in the low back area; and pain duration, intensity, and frequency were significantly decreased in the shoulder and wrist after tailored rehabilitation education. In addition, pain duration, intensity, and frequency showed a greater significant decrease after tailored rehabilitation education in the mild pain group than in the severe pain group.ConclusionsThis study found that work-related musculoskeletal pain was reduced after tailored rehabilitation education, especially in the shoulder, wrist, and low back.

The Computer-Vision Symptom Scale (CVSS17): development and initial validation.

To develop a questionnaire (in Spanish) to measure computer-related visual and ocular symptoms (CRVOS). A pilot questionnaire was created by consulting the literature, clinicians, and video display terminal (VDT) workers. The replies of 636 subjects completing the questionnaire were assessed using the Rasch model and conventional statistics to generate a new scale, designated the Computer-Vision Symptom Scale (CVSS17). Validity and reliability were determined by Rasch fit statistics, principal components analysis (PCA), person separation, differential item functioning (DIF), and item-person targeting. To assess construct validity, the CVSS17 was correlated with a Rasch-based visual discomfort scale (VDS) in 163 VDT workers, this group completed the CVSS17 twice in order to assess test-retest reliability (two-way single-measure intraclass correlation coefficient [ICC] and their 95% confidence intervals, and the coefficient of repeatability [COR]). The CVSS17 contains 17 items exploring 15 different symptoms. These items showed good reliability and internal consistency (mean square infit and outfit 0.88-1.17, eigenvalue for the first residual PCA component 1.37, person separation 2.85, and no DIF). Pearson's correlation with VDS scores was 0.60 (P < 0.001). Intraclass correlation coefficient for test-retest reliability was 0.849 (95% confidence interval [CI], 0.800-0.887), and COR was 8.14. The Rasch-based linear-scale CVSS17 emerged as a useful tool to quantify CRVOS in computer workers. : Spanish Abstract.

Comparison of Ocular Surface Disease Index and Tear Osmolarity as Markers of Ocular Surface Dysfunction in Video Terminal Display Workers

To compare the Ocular Surface Disease Index (OSDI) questionnaire and tear osmolarity, to screen ocular surface alterations in video display terminal (VDT) users. Cross-sectional study. Sixty-four VDT workers were screened for ocular surface alterations using OSDI and tear osmolarity. Furthermore, tear film break-up time (TBUT), fluorescein corneal stain, and assessment for meibomian glands dysfunction (MGD) were carried out. The alteration of 2 or more among these parameters was considered a sign of ocular surface dysfunction. Data for the statistical analysis were obtained from the eyes with the worst tear osmolarity score. Main outcome measures were OSDI and tear osmolarity. For the statistical analysis the receiver operating characteristic (ROC) curves and Spearman correlation coefficient were used. A P < .05 was considered statistically significant. The area under the ROC curve (AUC) for tear osmolarity (ranging from 0.71 to 0.86) showed, for all the classification variables considered, statistically significantly higher values than those obtained with OSDI (ranging from 0.51 to 0.58) (P < .01). Furthermore, tear osmolarity showed a direct correlation with corneal stain and ocular surface dysfunction and an inverse correlation for TBUT. No correlation was found between OSDI and the parameters considered. Tear osmolarity can be considered a more reliable test than OSDI, when screening VDT users for possible ocular surface alterations.

A Survey on the Risk Factors Analysis and Evaluation for the types of VDT Work

Objective: The purpose of this study was to analyze the risk factors of MSDs for the types of office work. Background: Physical risk factors of VDT(Video Display Terminal) associated with shoulder and neck musculoskeletal disorders(MSDs) include static work postures and workstation status. Method: In this study, office work was divided into data search, data entry and design work(drawings, etc.), and then we were surveyed 7 major work places which was included these works. We recorded working postures and obtained still images, depending on the types of office work. Then, RULA(Rapid Upper Limb Assessment) and ROSA(Rapid Office Strain Assessment) were used to analysis the risk factors. Results: The results of RULA showed that design work was under risk levels and required change, but ROSA showed that data entry and design work were high risk. The RULA is to evaluate the level of risk factors based on the working posture; on the other hand, the ROSA is to consider the use of peripheral, same as chair, keyboard/mouse, monitor and computer workstations. Conclusion: Conclusions of this study, the office work is necessary to identify the risk factors caused by the use of peripheral, as well as working posture.<BR>

Cupping for Treating Neck Pain in Video Display Terminal (VDT) Users: A Randomized Controlled Pilot Trial

This was a randomized controlled pilot trial to evaluate the effectiveness of cupping therapy for neck pain in video display terminal (VDT) workers. Forty VDT workers with moderate to severe neck pain were recruited from May, 2011 to February, 2012. Participants were randomly allocated into one of the two interventions: 6 sessions of wet and dry cupping or heating pad application. The participants were offered an exercise program to perform during the participation period. A 0 to 100 numeric rating scale (NRS) for neck pain, measure yourself medical outcome profile 2 score (MYMOP2 score), cervical spine range of motion (C-spine ROM), neck disability index (NDI), the EuroQol health index (EQ-5D), short form stress response inventory (SRI-SF) and fatigue severity scale (FSS) were assessed at several points during a 7-week period. Compared with a heating pad, cupping was more effective in improving pain (adjusted NRS difference: -1.29 [95% CI -1.61, -0.97] at 3 weeks (p=0.025) and -1.16 [-1.48, -0.84] at 7 weeks (p=0.005)), neck function (adjusted NDI difference: -0.79 [-1.11, -0.47] at 3 (p=0.0039) and 7 weeks (p<0.0001)) and discomfort (adjusted MYMOP2 difference score: -0.72 [-1.04 to -0.40] at 3 weeks and -0.92 [-1.24, -0.60] at 7 weeks). Significant improvement in EQ-5D was observed at 7 weeks (1.0 [0.88, 1.0] with cupping and 0.91 [0.86, 0.91] with heating pad treatment, p=0.0054). Four participants reported mild adverse events of cupping. Two weeks of cupping therapy and an exercise program may be effective in reducing pain and improving neck function in VDT workers.

Effectiveness of an ergonomic intervention on work-related posture and low back pain in video display terminal operators: A 3 year cross-over trial

This study investigated the effectiveness of a workstation ergonomic intervention for work-related posture and low back pain (LBP) in Video Display Terminal (VDT) workers. 100 VDT workers were selected to receive the ergonomic intervention, whereas 100 were assigned to a control group. The two groups were then crossed-over after 30 months from baseline. Follow-ups were repeated at 5, 12, and 30 months from baseline and then at 6 months following crossover. Outcomes: Work-related posture and LBP point-prevalence using the Rapid Entire Body Assessment method and a Pain Drawing, respectively. The ergonomic intervention at the workstation improved work-related posture and was effective in reducing LBP point-prevalence both in the first study period and after crossover, and these effects persisted for at least 30 months. In conclusion, our findings contribute to the evidence that individualized ergonomic interventions may be able to improve work-related posture and reduce LBP for VDT workers.

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.

Assessment of Subjective Stress in Video Display Terminal Workers

Stress assessment in the workplace has been focused on its environmental, psychological and biological aspects. We carried out an evaluation of the subjective components of stress in a working population of 60 subjects employed in a large Public Service, 30 Video Display Terminal (VDT) workers (15 men and 15 woman) and 30 office-workers not assigned to VDT (15 men and 15 woman), by using the "Rapid Stress Assessment Scale": a short questionnaire of easy administration in work environment. VDT workers of both sexes showed higher total stress score vs. office workers (respectively p<0.05, p<0.05). Gender differences were present: female VDT workers showed higher scores of clusters anxiety (p<0.001) and aggressiveness (p<0.05); male VDT workers' score were significantly higher in somatization (p<0.05) and aggressiveness cluster. Our results showed that in VDT workers are experienced greater subjective response to stress than "office workers" and confirm the gender differences in stress experiencing.

Effects of short-term VDT usage on visual functions

To evaluate the effects of short-term VDT usage on visual functions. Visual function of the video display terminal (VDT) operators before and after 1 hour VDT usage were assessed. These included refraction, amplitude of accommodation, near point of convergence, AC/A, phorias, fusional convergence and divergence, tear film break time (BUT) and aberrations. And the same situation was compared was the non-VDT usage. In comparison with pre-VDT use, amplitude of accommodation, BUT were significantly decreased (P < 0.05), near point of convergence, near lateral exophoria were significantly increased after VDT use (P < 0.05). Total, high order, 4th and 5th order aberrations were significantly greater after VDT use (P < 0.05). Short-term VDT work does have a significantly greater temporarily effect on visual function, tear film quality and visual quality.

Posture, muscle activity and muscle fatigue in prolonged VDT work at different screen height settings

With the increasing use of video display terminals (VDTs), there is growing concern over the corresponding increase in the number of health problems reported. Although much research has focused on identifying the optimal screen height, there is to date no consensus. This study aimed to investigate the effect of prolonged (89 min) VDT work at four different screen heights on head-neck posture, muscle activity and the development of muscle fatigue. The results show that lowering screen height, starting from 15 cm above the baseline (i.e. top of the screen level with eye height while sitting), decreased the ear-eye angle, increased the viewing angle, increased the viewing angle relative to the ear-eye line, and increased the muscle activity of the neck extensor muscles. There were also some significant time effects on postural angles and muscle activity. In this study there were only rare occurrences of muscle fatigue, defined as a simultaneous increase in EMG amplitude and a shift of the EMG power spectrum to lower frequencies. Muscle activity increased significantly in some muscles and for certain screen heights.