Use Of Display Terminals Research Articles

English

English

Influence of Prolonged Visual Display Terminal Use and Exercise on Physical and Mental Conditions of Internet Staff in Hangzhou, China.

To examine the effects of prolonged visual display terminal (VDT) working hours and exercise frequency on VDT-related symptoms, we recruited 944 Chinese internet staff for the study. A self-administered questionnaire survey was used to obtain the hours of daily VDT work, exercise frequency, and the physical and mental health of the participants. The daily VDT working time of participants was 8.7 hours. Musculoskeletal pain and eye complaints were prevalent, and the participants had poor mental health status. When daily VDT operation time was more than 11 hours, VDT-related symptoms, including backache (odds ratios (OR) = 3.59), wrist pain (OR = 1.88), hip pain (OR = 2.42), dry eyes (OR = 2.22), and ocular soreness (OR = 2.16) were more likely to occur, and an increased risk of serious occupational stress (OR = 6.75) and job burnout (OR = 2.66) was found in internet workers. Compared with those who never exercised, appropriate exercise frequency (three times per week) was helpful to relieve pain in the shoulders (OR = 0.28), neck (OR = 0.45), back (OR = 0.30), lower back (OR = 0.25), and wrists (OR = 0.38), as well as to prevent vision loss (OR = 0.33) and job burnout (OR = 0.42). Therefore, avoiding excessive VDT exposure and performing moderate exercise could protect the physical and mental health of internet staff from the adverse effects of VDT.

Effect of Late Night Studying and Excessive Use of Video Display Terminals on the Ocular Health of Medical Undergraduate Students in A Tertiary Care Hospital

Purpose: To evaluate the effect of late night study and excessive use of smart phones on the ocular health of medical undergraduate students. Design: An observational and cross-sectional study. Participants: Two hundred and fifty nine normal and healthy M.B.B.S students of age 18-25 y were included in the study over a period of two months. Methods: All the volunteers underwent an interview in form of a questionnaire. A complete ophthalmic examination was done including snellen visual acuity assessment, anterior segment examination with slit lamp, posterior segment with direct or indirect ophthalmoscopy; Schirmer’s test and tear film break up time. Results: A total of 259 subjects were included in the study and maximum subjects 160 (61.8%) were females. According to age, the students were divided in two groups as I and II with age of 17-20 y and 21-23 y respectively. Maximum 195 (75.3%) students belonged to group I. Maximum subjects 245 (94.5%) were using only smartphones and 239 (92.27%) subjects were using smartphones for more than 2 y. The maximum 136 (52.51%) students studied at night with maximum using tube light 112 (43.24%). A significant association was seen between the digital device used and age of the subject (p value=0.01). Number of symptoms experienced by the students showed significant relationship with the number of hours of smartphone usage (p value=0.02). Source of light in which the students studied at night was significantly associated with the number of symptoms experienced (p value=0.03). An association between usage of smartphones (hours) showed significant relationship with slit lamp examination (tear debri) and Schirmer’s (less than 15 mm) with p value of 0.03, 0.05 respectively. Conclusion: Source of light used to study at night and number of hours of use of devices shows relationship with symptoms. Smart phone users showed computer-related eye problems in more than half of the subjects.

Visual ergonomics of video-display-terminal workstations: Field measurements of luminance for various display settings

Electronic visual displays have shown a rapid technological evolution in the last two decades. With reference to the ergonomic requirements for video display terminal (VDT) workstations (ISO 9241), at an international level, attention is focused on the human–system interaction. With reference to visual ergonomics, the aim of this study is to assess luminance conditions through in-field measurements in order to evaluate: luminance and contrast ratios, luminance and contrast non-uniformities. The assessment was applied to widespread flat screen displays and repeated for fourteen combinations of Contrast–Brightness. The analysis carried out by the Authors shows the importance of realizing a simple and quick procedure to determine the performance levels of displays used in VDT workstations. The proposed assessment could be used as a practical tool for staff assigned to assess the risks arising from VDT use in the workplace within the Occupational Health and Safety Assessment Procedure.

Effect of the different ages and visual display terminal use on repositioning and lumbar muscle activity during continuous sitting.

[Purpose] The purpose of this study was to investigate the effect of different ages and visual display terminal (VDT) use on repositioning and lumbar muscle activity during continuous sitting. [Subjects] Thirteen males two groups: 7 males in their 20s, 6 males in their 40s participated in this study. [Methods] The two groups watched a lecture in a seated position under different conditions. L4 paraspinal muscle activity was recorded using a surface electromyography system. Repositioning was assessed using a video camera and Tekscan system. [Results] The repositioning times decreased significantly in the order to without a VDT in males in their 20s and 40s > with a VDT in males in their 20s > with a VDT in males in their 40s. The L4 paraspinal muscle activity significantly increased in order to without a VDT in males in their 20s and 40s < with a VDT in males in their 20s < with a VDT in males in their 40s. [Conclusion] The results of this study suggest that the number of repositioning movements during continuous sitting could affect lumbar muscle activity and could be an important factor for prevention of low back pain.

Visual Display Terminal use in Iranian bank tellers: Effects on job stress and insomnia.

Visual Display Terminals (VDTs) are equipments in many workplaces which their use may increase the risk of visual, musculoskeletal and mental problems including insomnia. To determine the relationship between duration of daily VDT use and insomnia among the Iranian bank tellers. We randomly selected 382 bank tellers working with VDT. Quality of sleep and stress information were collected by Athens Insomnia Scales (AIS) and Demand-Control Model (DCM) model respectively. Out of 382 participants, 127 (33.2%) had sleep complaints and 255 (66.8%) had no sleep disorders. Moreover, the insomnia symptoms' score were significantly high in the participants having more than 6 hours of daily VDT use after adjusting for multiple confounding factors (P < 0.001). There was no significant relationship between stress and insomnia. It seems that the low levels of stress and job satisfaction reduce the impact of VDT on sleep quality in tellers who worked less than 6 hours per day.

Visual Display Terminal Use Increases the Prevalence and Risk of Work‐related Musculoskeletal Disorders among Chinese Office Workers: A Cross‐sectional Study

Little is known about work-related musculoskeletal disorders (WMSDs) among computer users mainland China. The aim of this study was to estimate the prevalence of WMSDs in office workers in Beijing, and to determine risk factors for WMSDs in the neck (WMSDs-N). In a cross-sectional study, a self-administered questionnaire was delivered to 720 office workers who use a computer as a main working tool. Odds ratios (ORs) were calculated for risk factors. The prevalence of WMSDs of the neck, shoulder, wrist/hand, upper back and low back amongst office workers were 55.5, 50.7, 31.5, 26.2 and 6.6%, respectively. Both individual risk factor and working condition factors were found to be independently related to WMSDs-N. The WMSDs prevalence rates among office workers in Beijing, China, were high. The most affected area was the neck. Preventive measures for office work should be focused on the neck (e.g., rest breaks).

A monitoring tool of workers’ activity at Video Display Terminals for investigating VDT-related risk of musculoskeletal disorders

Today the risk factors related to the use of Video Display Terminals (VDT) are assessed by investigating the actual activities at the VDT through subjective questionnaires and/or quantitative measurements. Questionnaire outcomes are quite imprecise and seldom objective. Quantitative measurements (EMG recordings, electrogoniometers, motion analysis systems) mostly prevent subjects from moving freely while working at the VDT. The paper presents an automatic tool for the monitoring of activity at VDTs, using a quantitative, objective approach. The suitability of the proposed tool was fully tested in the laboratory, both in terms of functionalities, accuracy of the tool, and acceptance by the subjects involved. The outcomes show that the tool allows for a detailed analysis of VDT activities and may be used to improve VDT-related risk analysis with high accuracy and good acceptance by workers.

Neck–Upper Extremity Musculoskeletal Disorders Among Workers in the Telecommunications Company at Mansoura City

Objectives. This study was to determine the prevalence and work-related risk factors of neck-upper extremity musculoskeletal disorders (MSDs) among video display terminal (VDT) users. Methods. A comparative cross-sectional study was conducted; there were 60 VDT users and 35 controls. The participants filled in a structured questionnaire, had electrophysiological tests and an X-ray of the neck. Results. The prevalence of MSDs was higher (28.3%) among VDTs users compared to controls (14.3%) with no statistically significant difference. The prevalence of cervical disorders with or without radiculopathy ( 18.3%) was the most common disorder followed by carpal tunnel syndrome (6.6%). The mean (SD) age of MSD cases (51 ± 7.2 years) was statistically significantly higher than of the controls (42.8 ± 9). Physical exposure to prolonged static posture (OR: 6.9; 95% CI: 0.83–57.9), awkward posture (OR: 5.5; 95% CI: 0.6–46.4) and repetitive movements (OR: 5.5; 95% CI: 0.65–46.4) increased risk of MSDs with a statistically significant difference for static posture only (p < .05). VDT users experienced more job dissatisfaction, work-overload and limited social support from supervisors and colleagues. Conclusion. VDT use did not increase the risk of neck–upper extremity MSDs. The risk increased with older age and static posture.

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.

Symptoms in a Population of Contact Lens and Noncontact Lens Wearers Under Different Environmental Conditions

To investigate ocular symptoms related to dryness in an adult population of contact lens (CL) and non contact lens wearers (n-CL) using video display terminals (VDT) for different periods of time under different indoor conditions related to air conditioning (AC) and heating units (HU) exposure. A questionnaire was distributed to 334 people within a university population of which 258 were part of the n-CL group and 76 of the CL wearers to assess symptoms of ocular discomfort potentially related to dryness. Only soft contact lens (SCL) wearers (n = 71) were included for further statistical analysis because of the reduced number of people wearing other lens types. A 2:1 match by gender group of 142 subjects in the n-CL group was used as a control sample. There was a marked difference between the prevalence of symptoms and the way they are reported by CL and n-CL wearers. Red eye, itching, and scratchiness are more common among CL wearers, but the difference is statistically significant only for scratchiness (p < 0.01, chi(2)). The vast majority of subjects who reported symptoms often and at the end of the day are significantly more prevalent among CL wearers (p < 0.01, chi(2)). Gender differences were also encountered. Female CL wearers reported more scratchiness than males in the n-CL wearing group (p = 0.029, chi(2)) and in the CL group (p < 0.008, chi(2)). Females wearing CL reported symptoms of red eye (p = 0.043, chi(2)) and scratchiness (p < 0.001, chi(2)) more significantly than those in the n-CL group. Within the CL group, the prevalence of symptoms occurring sometimes or often and at the end of the day was higher among females (p < 0.001, chi(2)). The use of VDT was associated with a higher level of scratchiness among CL wearers (p < 0.05, chi(2)). The number of hours working with VDTs seemed to be associated with an increase in the prevalence of burning sensation in the CL group (p < 0.01, chi(2)), whereas symptoms like red eye and scratchiness also increased significantly among n-CL wearers. Compared to n-CL wearers, all symptoms increase in CL wearers in environments with AC and HU, except excessive tearing. However, these differences are only statistically significant for scratchiness. Our results show that people who wear soft CL and work with VDTs for longer periods of time are more likely to develop symptoms like eye burning and scratchiness than n-CL wearers. This risk could be higher for women than men. Scratchiness and the appearance of symptoms near the end of the day are typically associated with ocular discomfort during CL wear in this sample, and clinicians should question their patients about these symptoms to anticipate serious discomfort.

Are there differences between ‘visual symptoms’ and specific ocular symptoms associated with video display terminal (VDT) use?

To assess the reliability of self-reported symptoms of asthenopia associated with VDT use (as characterized by general visual symptoms, headache and specific ocular symptoms) for both continuing soft contact lens (SCL) wearers and former SCL wearers who had undergone successful laser-in-situ-keratomileusis (LASIK) surgery. Methods Forty generally healthy adults, aged between 24 and 44 years, were asked to complete a 13 page questionnaire that included requests for information on general visual symptoms, headache and specific ocular symptoms such as dry eye associated with VDT use. The adults were either long term successful soft contact lens wearers ( n = 20) or a similar group who had then undergone successful LASIK refractive surgery for myopia 2 years prior to the questionnaire being provided. Results Most subjects (70%) reported experiencing some visual symptoms sometimes, 62.5% reported headaches sometimes, and 82.5 % reported specific ocular symptoms sometimes. There were no obvious differences between the two groups either in the reported frequency or severity (by visual analogue scale, VAS) of visual symptoms, headache or specific ocular symptoms. However, while the reporting of headache showed no obvious association with the number of specific ocular symptoms reported, the latter showed a clear correlation with the reporting of the severity of visual symptoms ( p < 0.001). Discussion The results indicate that when an individual reports visual symptoms, they may actually be providing recall of specific ocular symptoms. Therefore, contrary to an often common practice, visual symptoms should be assessed separately to specific ocular symptoms such that the appropriate management can be selected. The results also indicate that previous contact lens wearers who have undergone successful LASIK are still likely to experience some visual and specific ocular symptoms when undertaking computer based work on a regular basis.

The Influence of Visual Display Terminal Use on the Physical and Mental Conditions of Administrative Staff in Japan

Visual display terminals (VDT) are standard equipment for many office workers. Their use, however, may increase the risk of developing adverse conditions related to vision, the musculoskeletal system, and mental health. We carried out a survey among 3070 workers aged 18 to 67 years (mean, 39.9 years) at a prefectural administrative office, in which 76% of subjects were visual display terminal (VDT) users. We examined the relationship between duration of daily VDT use and eyestrain, neck or upper extremity pain, back pain, and mental health, and estimated the effect of breaks and rest during VDT work on these symptoms. The 12-item General Health Questionnaire (GHQ-12: total scores ranged from 0 to 12) was used to identify potential poor mental health status, and subjects with 4 or more were considered to have symptoms of psychological distress. Seventeen percent of subjects reported eyestrain, 19.1% reported upper extremity pain, 11.6% reported back pain, and 17% of subjects had GHQ-12 scores of 4 or higher. Logistic regression analysis showed that duration of daily VDT use and lack of breaks and rest during VDT work were significantly associated with eyestrain, neck or upper extremity pain, back pain, and psychological distress. In order to protect users from the adverse effects associated with VDT work, reducing daily VDT exposure, taking breaks, and rest during VDT work are important.

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.

Marked reduction and distinct patterns of eye blinking in patients with moderately dry eyes during video display terminal use.

To analyze the spontaneous eye-blink rate (SEBR) and blinking pattern in patients with moderately dry eyes during video display terminal (VDT) use. The SEBR of 30 patients with dry eye syndrome (median age 44.8 years, range 18 - 67 years) was measured using a computer-based video analysis system. Only complete eye blinks were recorded during 10 min of conversation, during initial VDT use and again after a preceding work period of 30 min. In comparison with SEBR during conversation (mean value 16.8 blinks/min, standard deviation 16.8 blinks/min) the SEBR significantly decreased during initial VDT use (6.6+/-4.8; P<0.001) and remained significantly decreased during re-measurement after 30 min (5.9+/-4.6; P<0.001). SEBR was not significantly different between initial VDT use and re-measurement after 30 min ( P=0.65). The SEBR was characterized by marked interindividual variability during conversation and VDT use. No significant correlation was found between SEBR (either during conversation or during VDT use), and the quality (tear break-up time) or quantity (Schirmer I test, Jones test) of the tear film. Typical blinking patterns were found to be (1). a relatively time-independent, irregular pattern, (2). an initial phase of 2-4 min with shorter inter-eye-blink intervals, and (3). alternating periods of higher and lower inter-eye-blink intervals. Reduction of the SEBR during VDT use is primarily determined by marked visual attention, resulting in an exacerbation of dry eye symptoms in predisposed humans. High interindividual variability and distinct patterns of eye blinking may be key factors in further clarification of VDT-eye interactions and develop individually designed solutions to prevent desiccation during VDT use.

Characteristics of spontaneous eyeblink activity during video display terminal use in healthy volunteers.

To analyse the spontaneous eyeblink rate (SEBR) and inter-eyeblink intervals (IEBI) of normal volunteers before and during video display terminal (VDT) use. The SEBR of 51 normal volunteers was measured by counting the absence of the corneal reflex using a computer-based video analysis system. Only complete eyeblinks were recorded within 10 min under three different conditions: during a conversation, during VDT use without corneal anaesthesia, and during VDT use with corneal anaesthesia. The IEBI (in seconds) were determined to study individual time-dependent changes of SEBR. In comparison with SEBR during conversation (mean 15.54 eyeblinks/min, standard deviation +/-13.74 eyeblinks/min) the SEBR decreased significantly during VDT use without corneal anaesthesia (5.34 +/- 4.53 eyeblinks/min). Corneal anaesthesia further significantly reduced SEBR (2.78 +/- 2.77 eyeblinks/min). The SEBR was characterized by marked interindividual variability, ranging between 11 and 664 eyeblinks/10 min during conversation, between 4 and 189 eyeblinks during VDT use without corneal anaesthesia and between 1 and 119 eyeblinks at VDT use with corneal anaesthesia. No significant correlation between SEBR (during conversation or during VDT use) and quality (break-up time) or quantity (Schirmer I test, Jones test) of the tear film could be detected. Evaluation of the IEBI revealed three different types of eyeblink pattern during VDT use without corneal anaesthesia. Type 1 was characterized by a very low SEBR (0-2 eyeblinks/min) and relatively homogeneous distribution of eyeblinks, type 2 showed a moderate SEBR (1.2-8.5 eyeblinks/min) including three further subtypes. Type 3 was characterized by a high SEBR (6.8-18.9 eyeblinks/min) of regular or irregular pattern. VDT use is associated with a profound decrease of the SEBR in healthy subjects. There are marked interindividual differences in SEBR and no correlation between the SEBR and ocular tear film parameters in normal eyes. The SEBR is further reduced by corneal anaesthesia. The presence of different patterns of eyeblinking may be related to various exogenous and endogenous factors and may lead to a better understanding of ocular reactions during VDT use.

Changes in postural risk and general health associated with a participatory ergonomics education program used by heavy video display terminal users: A pilot study

To determine if a brief, participatory ergonomics education program was associated with changes in work posture and general health of heavy video display terminal (VDT) users, 23 full-time VDT users participated in an on-site, small-group, 60-minute ergonomics education session and 1 week later an individual 15-minute follow-up session at their workstation. Posture was assessed by a blinded tester who scored videotape records to complete the Postural and Repetitiveness Risk Factors Index (PRRI), and general health status was assessed via self-administered Short-Form 36 Health Survey (SF-36) questionnaire before the intervention and again 5 weeks later. Five weeks after the 60-minute session, PRRI scores were 19% lower than were preintervention scores (p < 0.01), indicating lower postural risk. SF-36 physical (2% higher) and mental (4% higher) component scores were not statistically different, however, before and after intervention (p > 0.05). Although the participatory ergonomics education program was associated with improved work posture (PRRI scores) after 5 weeks, general physical and mental health (SF-36 scores) did not change within this time period. These results suggest that a participatory ergonomics program, which is of short duration and minimally disruptive to the normal workplace routine, may have a rapid effect on improving work posture. Although awkward posture is thought to be a risk factor for work-related musculoskeletal disorders, multigroup and long-term randomized trials are required to establish the effectiveness of participatory ergonomics programs in reducing the incidence and severity of musculoskeletal disorders associated with heavy VDT use. J HAND THER. 2003;16:29-35.

VDT eyeglasses—multifocal lenses for near distance use

This paper discussed eyeglasses for middle-aged video display terminal (VDT) users and how middle-aged VDT users can obtain the proper eyeglasses for task that they perform in their office. First, the loss of visual function of middle-aged workers and the characteristics of modern eyeglass lenses are described in terms of VDT use. Then, a method for selecting the proper VDT glasses from an eyeglass shop was described. The discussion is particularly important in countries like Japan, where most workers do not have at their disposal experts to assist in the selection of the proper eyewear for their work-related tasks.

VDT Health Hazards

The proliferation of end user computing creates a host of management issues. One such issue involves the potential health hazards associated with video display terminal (VDT) use. Both managers and end users must address this issue. Managers must strive for a healthy and productive working environment for end users. Eliminating or reducing lost work days and improving worker productivity in turn relates to the organization’s profitability. VDT related health issues are important to end users, managers, and the organization as a whole. This article outlines major health issues (e.g., vision problems, musculoskeletal disorders, and radiation effects on pregnancy) associated with VDT use. It provides practical suggestions for both end users and managers to help eliminate or reduce the potential negative health effects of VDT use.

Video display terminal workstation improvement program: I. Baseline associations between musculoskeletal discomfort and ergonomic features of workstations.

Associations between selected sites of musculoskeletal discomfort and ergonomic characteristics of the video display terminal (VDT) workstation were assessed in analyses controlling for demographic, psychosocial stress, and VDT use factors in 273 VDT users from a large administrative department. Significant associations with wrist/hand discomfort were seen for female gender; working 7+ hours at a VDT; low job satisfaction; poor keyboard position; use of new, adjustable furniture; and layout of the workstation. Significantly increased odds ratios for neck/shoulder discomfort were observed for 7+ hours at a VDT, less than complete job control, older age (40 to 49 years), and never/infrequent breaks. Lower back discomfort was related marginally to working 7+ hours at a VDT. These results demonstrate that some characteristics of VDT workstations, after accounting for psychosocial stress, can be correlated with musculoskeletal discomfort.