Visual Display Terminal Work Research Articles

VDT 작업에서 두부전방자세 위험수준에 따른 목의 피로와 Flexion-Relaxation 변수에 관한 연구

Objective: The aim of this study is to quantify the neck fatigue of the office in Visual Display Terminal (VDT) work using the parameters of the flexion-relaxation phenomenon. Background: VDT work comprises a large proportion of the office worker tasks. Although VDT work requires relatively less loads, it can stress the neck and shoulders of the workers who work for a long period time with awkward sitting postures. In spite of that many office workers are suffering from neck and shoulder pains, the current solution for musculoskeletal disorders of office workers is only a management approach. Thus, it is important to precisely quantify the fatigue of VDT workers for reducing the prevalence of musculoskeletal disorders in office workers and for improving working environment. Method: For this experiment, 23 males were recruited to compare flexion-relaxation parameters such as Flexion-Relaxation Ratio (FRR) and On/Offset angle, and subjective discomfort (Borg CR-10 scale) before and after VDT task during 50 minutes. Participants were divided into two groups (forward head posture (FHP) high risk group and FHP low risk group) based on the pre-FHP test. Results: FRP parameters changed after VDT task. The FRR was significantly decreased and On/Offset angles showed an increasing trend after the task. CVA was slightly lower in FHP high risk group during 50 minute of VDT task. Using this result, it was found that high risk group of FHP was maintained at a lower posture for a long time. In addition, the subjective discomfort also increased after task. Conclusion: Based on these results, VDT work causes fatigue to the worker. And this fatigue can be quantified using FRP parameters. In addition, it was confirmed that FRR can be used as an index to confirm the abnormality of neck. Application: These results can be used to quantify the fatigue caused by VDT work in office workers, and to further validate the improvement of musculoskeletal disorders.

Effects of MaquiBright® on improving eye dryness and fatigue in humans: A randomized, double-blind, placebo-controlled trial

This study aims to investigate the effects of MaquiBright®, also known as BrightSight®, a standardized maqui berry extract, on improving eye dryness and fatigue in Japanese subjects (aged 30–60 years) experiencing eye dryness, eye fatigue, and ≥4 h of visual display terminal (VDT) work daily. Seventy-four participants were equally but randomly assigned to either a MaquiBright® (MB) or a placebo (P) group, wherein each participant consumed one capsule daily for 4 weeks of the appropriate treatment (MaquiBright® 60 or 0 mg). Eye dryness and fatigue were measured using the Schirmer's test, tear break-up time (BUT) test, pupillary response, and flicker test before intake and 4 weeks after intake. Furthermore, subjective symptoms were assessed using the Visual Analogue Scale (VAS) method and the Dry Eye–related Quality of Life Score (DEQS) questionnaire. The MB group demonstrated a significantly higher lacrimal fluid production in both eyes (increased 6.4 ± 8.1 mm, P = 0.005) in Schirmer's test compared to the P group before VDT load (playing a video game) at 4 weeks after intake. In the VAS method after VDT load, the reduction of subjective symptoms in eye fatigue (P = 0.047) and stiff shoulders (P = 0.035) were significantly higher in the MB group than in the P group as well as bothersome ocular symptoms (P = 0.037) by the DEQS. No adverse events were reported. Thus, the consumption of 60 mg of MaquiBright® per day for 4 weeks reduced eye dryness and seemed to alleviate eye fatigue.

Fundamental study on fatigue measurement in VDT work from speech analysis

AbstractWe aimed at developing a simple fatigue measurement system, so far the influence of the noise is small under laboratory environment and the experimenter side who uses a simulator. We have been studying fatigue measurement in a manageable environment. In order to show the effectiveness of our proposed method in a real environment, we collected fatigue measurement indexes before and after work for technical engineers of Software Development Company operating visual display terminals (VDT) work, changes before and after were compared and examined. As a result, in the conventional indexes, a significant difference was found in the pulse rate and the flicker value. We found that there are significant differences between before and after some speech of fundamental frequency, speech power, and period of speech indexes. In VDT work, there was a difference in flicker value as a fatigue measurement index, which was also supported by subjective symptoms and self‐evaluation results. In addition, since significant differences were also found in the speech index, in the work centering on the VDT work as well as the bicycle simulator so far, it was shown that speech indexes can be effective indicators.

What Have We Learned From the Osaka Study?

To summarize the results of a cross-sectional epidemiologic study of Japanese office workers who use visual display terminals (VDTs). Workers in a pharmaceutical company head office were recruited. Participants were requested to complete a questionnaire on symptoms of dry eye disease (DED) and evaluations using the Work Limitations Questionnaire, International Physical Activity Questionnaire, Subjective Happiness Scale, and Pittsburgh Sleep Quality Index. Evaluations of ocular status, including conjunctival and corneal vital staining with lissamine green and fluorescein, measurement of tear film breakup time, and the Schirmer test, were performed. The Japanese 2007 diagnostic criteria for DED were implemented. The prevalence of DED among VDT workers was high. Definite DED was present in 11.6% (18.7% women and 8.0% men) of participants, and probable DED was present in 54.0% (57.8% women and 52.1% men). Total loss of workplace productivity was significantly greater in the definite DED group (4.82%) than in the probable DED group (4.06%) and the non-DED group (3.56%, P < 0.014, trend test). Participants with definite DED had significantly lower physical activity scores than those without DED (P = 0.025). Subjective happiness correlated with the dry eye symptom score (r = -0.188; P < 0.001). Participants with DED reported poor sleep quality at a higher rate compared with those without DED (45% vs. 34%), with a significant difference in the global score (P = 0.002). Dry eye is prevalent among VDT workers. Its impacts on work productivity, physical activity, and sleep quality warrant further study.

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.

Amelioration of Visual Display Terminal-induced Ocular Fatigue by Aqueous Extracts of &lt;i&gt;Perilla frutescens &lt;/i&gt;var. acuta

In this study, we investigated the effects of Perilla frutescens var. acuta aqueous extract (PFA) on eyestrain using in vitro, ex vivo, and clinical tests. We confirmed the antioxidant activity of compounds present in the extract by using high-performance liquid chromatography. PFA contains antioxidant compounds such as rosmarinic acid, luteolin-7-O-glucuronide, and apigenin-7-O-glucuronide, and has been shown to inhibit reactive oxygen species generation in C2C12 muscle cells. In an ex vivo study, PFA inhibited the carbachol (100 μM)-induced contraction of ciliary muscle from rabbit eyeball. We then investigated the mechanism by which PFA caused muscle relaxation and found that it effectively increased cyclic GMP production and inhibited PDE5A activity, but did not affect the cyclic AMP pathway, in cultured human aortic smooth muscle cells. In addition, PFA (50, 100, and 200 µg/mL) dose-dependently decreased basal intracellular calcium in smooth muscle cells and attenuated the endothelin-1-stimulated increase in intracellular calcium. Finally, we performed a clinical study to evaluate the effects of PFA on the near point of accommodation (NPA) after visual display terminal (VDT) work. Thirty participants were randomized to either PFA (500 mg/day) or placebo, and intake for one consecutive week. NPA was evaluated before and after 2 h of VDT work, and was found to be improved in the PFA-treated group. Thus, our findings show that PFA may ameliorate visual fatigue.

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.

A model for evaluating visual fatigue under LED light sources based on long-term visual display terminal work

Using data derived from eight hours work at a visual display terminal, a model for evaluating visual fatigue under LED light sources has been developed based on five ophthalmological parameters and three physiological signals. A simplified model based on one ophthalmological parameter and one physiological signal is also proposed. Both models show a high correlation with subjective data and are confirmed by a validation experiment. The results also show that the visual fatigue occurring after eight hours of visual display terminal work under LED lighting is rather small.

Visual fatigue following long-term visual display terminal work under different light sources

Although visual display terminals have been used in office work for many years, research on the effect of long time work using them is still insufficient. Also, the impact of a LED light source for all day work is not clear. In this paper, the visual fatigue caused by long-term VDT work under fluorescent and LED luminaires was investigated though subjective reports of symptoms, ophthalmological parameters and physiological signals. The results show that visual fatigue becomes more serious with increasing time spent at VDT work. Compared to fluorescent luminaires, the LED luminaires produced significantly greater near point accommodation, blink amplitude and oxygen saturation but less dry eye symptoms, less best corrected distance visual acuity and less high-frequency electrocardiogram power as time passed, although all were of small effect size. Although the participants carried out eight hours of VDT work under the two light sources, at the end the symptom ‘tired eyes’ was rated as moderate while all the other reported symptoms were rated as slight.

Effect of the craniocervical brace on craniocervical angle, thoracic kyphosis angle, and trunk extensor muscle activity during typing in subjects with forward head posture.

The relationship between forward head posture (FHP) and thoracic kyphosis has been a subject of interest in the rehabilitation field for visual display terminal workers. The aim of this study was to investigate the immediate effects of the craniocervical brace use on craniocervical angle (CCA), thoracic kyphosis angle (TKA), and trunk extensor muscle activity. Twelve young male subjects with forward head posture (21.6±1.9 years) participated in this study. We compared CCA & TKA and trunk extensor muscle activity between with and without application of the craniocervical brace during visual display terminal work. When wearing the craniocervical brace, the subjects demonstrated significantly greater CCA at the start and the end of the task and less change in CCA during the task (p < 0.05). While non-significantly less TKA was seen at the start of the task, significantly less TKA was observed at the end of the task when using the craniocervical brace (p < 0.05). The craniocervical brace use also led to significantly less change in TKA (p < 0.05). There was no significant difference in the trunk extensor muscle activity. Use of the craniocervical brace decreased FHP immediately, lessened thoracic kyphosis over time, and prevented the worsening of FHP and thoracic kyphosis during visual display terminal work.

Effect of Tactile Feedback on Trunk Posture and EMG Activity in People With Postural Kyphosis During VDT Work

Background: Recently, there has been an emphasis on the use of interventions with biofeedback information for the maintenance or correction of posture. Objects: This study assessed the change of trunk posture and trunk muscle activation when people exhibiting postural kyphosis performed visual display terminal work with or without a contact feedback device (CFD). Methods: Eighteen right-handed individuals were recruited. Thoracic angle and right thoracic erector spinae (TES) muscle amplitude were analyzed. There were two sessions in these experiments. The control session involved 16 minutes of typing without a CFD, and the CFD session involved 16 minutes of typing with a CFD. The visual analog scale score was analyzed with a paired t-test, and the kinematic and electromyography data were analyzed through two-way repeated analysis of variance. Results: The paired t-tests revealed that subjects had significantly less pain after the CFD sessions than after the control sessions (p<.05). Significant main effects by session and by time were observed in the thoracic kyphosis angle (p<.05). There was a significant session×time interaction for TES amplitude (p<.05), along with significant main effects by session and by time (p<.05). Conclusion: The CFD caused people with postural kyphosis to straighten and to activate their TES continuously, even though they were habituated to bend their bodies forward. Therefore, the CFD was a beneficial treatment tool.

Research the Effects of Thoracic and Lumbar Support Fixtures on Forward Head Posture during Visual Display Terminal Work

Research the Effects of Thoracic and Lumbar Support Fixtures on Forward Head Posture during Visual Display Terminal Work

Graphical Notification to Maintain Good Posture during Visual Display Terminal Work

Visual Display terminal (VDT) work typically results in low-level static back, shoulder and neck muscles loading, as well as static spine loading. Improving sitting posture can reduce such loadings. We developed a posture notification system to make a user aware of poor posture by displaying illustrations of problematic posture. The proposed system encourages motivation through competition using a feature that allows users to share their sitting posture and posture score with other users. In an experiment, six participants were asked to perform everyday VDT work using the proposed system. The experimental results indicated that the proposed system made participants aware of their poor posture However, the proposed system was not effective at motivating participants to maintain good posture. To motivate participants to maintain a good posture, we must adopt additional self-competition and normalization features.

Prevalence of dry eye disease in visual display terminal workers: a systematic review and meta-analysis

ObjectiveTo evaluate the prevalence and risk factors of dry eye disease (DED) in workers using visual display terminals (VDT).DesignSystematic review and meta-analysis.Data sourcesWe searched PubMed, Cochrane Library, Embase and Science...

An analysis of pulse wave signals during visual display terminal operations.

In this paper, participants operated visual display terminals (VDT); the authors analyzed their pulse wave signals to develop objective indices for diagnosing and assessing VDT-induced. The experiment used 30 healthy undergraduates test subjects; each subject operated static PC for 4 hours. The pulse waves of local blood volumes in the test subjects' finger-tips were measured every 30 minutes for 2 minutes. After the experiment, the pulse wave parameters were analyzed. All test subjects exhibited signs of visual fatigue according to the fatigue scale results. There were significant differences of heart rate (HR), which clearly declined before and after the experiment (P<0.01). The indexes RMSSD, SDNN, P3, P4, P5, P6, and TP had significant differences (P<0.01) and all rose. The positions of the main and dicrotic waves advanced (P<0.01). The experiment parameters prompted significant changes; pulse wave forms changed during VDT work. Based on these results, pulse wave analysis holds promise as an effective, noninvasive technique for measuring VDT fatigue.

Screening of dry eye disease in visual display terminal workers during occupational health examinations: The Moriguchi study.

The aim of this study was to estimate the prevalence of dry eye disease (DED) in Japanese visual display terminal (VDT) workers and identify simple methods for screening DED during occupational health examinations. This study involved 369 (331 men and 38 women; mean age, 44.4 [8.8] years) workers engaged in PC development with approximately 6 hours of VDT use daily. The participants completed questionnaires on dry eye and physical symptoms affecting QoL, and their ability to keep their eyes open for 10 seconds was tested for DED screening. They also underwent assessment of conjunctival and corneal vital staining with lissamine green and fluorescein, measurement of tear film breakup time, and Schirmer's test for DED diagnosis. Sensitivity, specificity, and positive predictive value of the screening methods were assessed. The DED group included 218 (definite, 14; probable, 204) participants. They had markedly high frequencies of 11 dry eye symptoms, especially ocular fatigue (OR, 17.1; 95% CI, 9.9 to 29.7) and dry sensation (OR, 8.2; 95% CI, 3.6 to 18.4), and were more often unable to keep their eyes open for 10 s. With either ocular fatigue or dry sensation as the cutoff criterion, the sensitivity, specificity, and positive predictive value were 89.9, 66.9, and 79.7%, respectively. Approximately 60% of the VDT workers were diagnosed with DED on the basis of diverse eye symptoms affecting their ability to work. The dry eye symptom questionnaire and 10-s eye-opening test are simple, noninvasive, and inexpensive methods for screening DED during occupational health examinations.

A Study on the VDT Workstations Usage for Office Workers

Objective and Background: Due to increase in Musculoskeletal Disorders (MSDs) relating to computer use, a number of ergonomics recommendations have been proposed in order to tackle this problem. However, some of these recommendations have been conflicting. Method: This study was to survey the VDT (Visual Display Terminal) use of office workers. The subjects were 452 workers at 13 places of business and the data were collected by self-administered questionnaire. Results: As a result, prevalence of self-reported MSDs of all VDT workers was 90.2% and shoulder took up 57.0% and neck 38.3% by symptom part of body. The population of computer use of more than 6h/day was 84.5%, and 33.8% also reported using the VDT 2~3h/day without the rest time. Desktop computer users were 95.6%, and a 17-inch monitor accounted for 42.0% among the desktop users. As a result of satisfaction survey on overall computer work, 21.1% of the total respondents said satisfied, desk complaint was about 24.6%, and chair complaint was 33.4%. Despite the importance of computer environment, satisfaction was from fair to uncomfortable. Conclusion and Application: In conclusion, office workers are prone to the MSDs due to their work environment. Additionally, this study found that task was a significant effect for the majority of dependent variables, and therefore, the improvement of computer workstations work environment is urgent, and the improvement of desk height adjustment, chair seat size (length, width), backrest condition, location of keyboard (mouse) and arm rest is required.

Advanced dry eye screening for visual display terminal workers using functional visual acuity measurement: the Moriguchi study

PurposeTo evaluate the validity of a dry eye (DE) screening method in visual display terminal (VDT) workers using functional visual acuity (VA) measurement combined with a symptoms questionnaire, and to...

Meibomian gland dysfunction determines the severity of the dry eye conditions in visual display terminal workers.

ObjectiveTo explore meibomian gland dysfunction (MGD) may determine the severity of dry eye conditions in visual display terminal (VDT) workers.MethodologyProspective, case-control study carried out in China.106 eyes of 53 patients (VDT work time >4 hour per day) were recruited as the Long time VDT group; 80 eyes of 40 control subjects (VDT work time ≤4 hour per day) served as the Short time VDT group. A questionnaire of Ocular Surface Disease Index (OSDI) and multiple tests were performed. Three dry eye tests: tear film breakup time (BUT), corneal fluorescein staining, Schirmer I test; and three MGD parameters: lid margin abnormality score, meibum expression assessment (meibum score), and meibomian gland dropout degree (meiboscore) using Keratograph 5 M.Principal FindingsOSDI and corneal fluorescein score were significantly higher while BUT was dramatically shorter in the long time VDT group than the short time VDT group. However, the average of Schirmer tear volumes was in normal ranges in both groups. Interestingly, the three MGD parameters were significantly higher in the long time VDT group than the short time one (P<0.0001). When 52 eyes with Schirmer <10 mm and 54 eyes with Schirmer ≥10 mm were separated from the long time VDT workers, no significant differences were found between the two subgroups in OSDI, fluorescein staining and BUT, as well as the three MGD parameters. All three MGD parameters were positively correlated with VDT working time (P<0.0001) and fluorescein scores (P<0.0001), inversely correlated with BUT (P<0.05), but not correlated with Schirmer tear volumes in the VDT workers.ConclusionsOur findings suggest that a malfunction of meibomian glands is associated with dry eye patients in long term VDT workers with higher OSDI scores whereas some of those patients presenting a normal tear volume.

Daily visual display terminal use and musculoskeletal disorders among Iranian bank tellers

Visual display terminals (VDTs) as one of the most important and useful equipment are used in offices and workplaces that may be created some health hazards, including work-related musculoskeletal disorders (WMSDs). The aims of this study were to (i) investigate the prevalence of WMSDs among Iranian bank tellers and (ii) to examine the demographic and work-related characteristics associated with that prevalence rate. In this cross-sectional study, 382 bank tellers who regularly working at VDTs stations were interviewed. The demographic, work characteristics and MSDs data were collected using specific questionnaire and standardized Nordic self-reporting Musculoskeletal Questionnaire. Hence, data analyses were carried out using IBM SPSS for Windows 20.0. As a result, 70.2% of participants reported the musculoskeletal problems within 12 past months in at least one of the body regions. The most prevalence was reported in the neck (37.4%) and low back (36.6%) regions, and the elbows (8.3%), and thighs (12.3%) were regions that reported with the least prevalence rate. Mean duration of daily VDT (DVDT) work in 268 subjects with musculoskeletal symptoms was 6.2 h (SD = ±2.2) and in other 114 subjects without symptoms, it was 5.5 h (SD = ±2.3). There was a positive significant relationship between DVDT work hours with reported musculoskeletal problems (P = 0.005). In conclusion, WMSDs in bank tellers happened in high rate (70.2%) and the most complain reported in neck and low back regions. The most consistently identified risk factor was a duration of DVDT use and inadequate break times.