Visual Display Terminal Users Research Articles

Short-Term Omega 3 Fatty Acids Treatment for Dry Eye in Young and Middle-Aged Visual Display Terminal Users.

To evaluate the effect of an omega 3 fatty acid (O3FA) oral supplement (2,400 mg/day) for 45 days on dry eye symptoms, tear production, stability, and conjunctival cytology in young and middle-aged visual display terminal (VDT) users. Institutional review board approval was obtained, and a randomized, double-blind, interventional study was done; eyes of 256 VDT users were randomized to receive 4 capsules twice daily for 45 days (O3FA group), each containing 180 mg of eicosapentaenoic acid and 120 mg docosahexaenoic acid. The O3FA group was compared with another group (n=266) who received 8 capsules of a placebo (olive oil). Patients were evaluated at baseline, 30 days, and 45 days. The primary outcome measure was an improvement in dry eye symptoms. Secondary outcome measures were improvement in the Nelson grade on conjunctival impression cytology, Schirmer test values, and tear film breakup time (TBUT). Means of groups (pretreatment, day 30, and day 45) were compared with repeated-measure analysis of variance. The relation between the outcome variables and VDT time was evaluated using linear regression. In the O3FA group, the mean symptom score differed significantly (P<0.005) (pretreatment, 30 days, and 45 days); the TBUT and Nelson grade also improved significantly but only after 45 days of intervention. Schirmer test values did not differ significantly after adjustment for multiple comparisons (P=0.010). The change was not significant in the placebo group. Consumption of 2,400 mg/day of O3FA supplement improves symptoms, tear stability, and conjunctival cytology but not tear production in symptomatic VDT users.

Blink Rate and Incomplete Blinks in Six Different Controlled Hard-Copy and Electronic Reading Conditions.

To evaluate spontaneous eye blink rate (SEBR) and percentage of incomplete blinks in different hard-copy and visual display terminal (VDT) reading conditions, compared with baseline conditions. A sample of 50 participants (29 females, age range, 18-74 years) were recruited for this study. All participants had good ocular health and reported no symptoms of dry eye (OSDI score < 15). Face video recordings were captured while participants observed in silence a landscape picture at 2 m (baseline) and during six different, 6-minute controlled reading experimental conditions. Texts were presented in electronic (tablet and computer display at 100% and 330% zoom levels) and hard-copy (text in book position in silence and aloud and text pasted on the computer display) formats. Video analysis was subsequently conducted to assess blink parameters. All reading conditions resulted in a decrease in SEBR when compared with baseline conditions (all P < 0.001), with the least negative impact corresponding to reading in a 330% expanded display. The percentage of incomplete blinks was found to increase when reading was conducted on an electronic platform, in contrast to hard-copy text. The high cognitive demands associated with a reading task led to a reduction in SEBR, irrespective of type of reading platform. However, only electronic reading resulted in an increase in the percentage of incomplete blinks, which may account for the symptoms experienced by VDT users. Spanish Abstract.

Change in tear film characteristics in visual display terminal users.

To evaluate changes in symptoms and tear film characteristics in young computer users. Fifty-one computer users and 26 controls were evaluated at the beginning and the end of the working day. Subjects with ocular or systemic disease, history of ocular surgery, use of contact lenses or glasses with antireflective surfaces, and use of topical or systemic medications were excluded from the study. Computer use duration, Ocular Surface Disease Index (OSDI) questionnaire, tear osmolarity, Schirmer test, tear break-up time (TBUT), and ocular surface vital dye staining were performed prevocationally and postvocationally. The mean age was 31.2 ± 6.3 years in computer users and 33.7 ± 5.8 in controls. The mean reported computer use was 6.9 ± 2.7 hours/day in computer users and 0.4 ± 0.5 hours/day in controls. The mean prevocational and postvocational values in computer users for OSDI, osmolarity, TBUT, and Schirmer test were 23.2 ± 16.6 and 27.0 ± 17.6, 306.6 ± 14.9 and 311.0 ± 12.5 mOsm/L, 13.9 ± 4.0 and 13.2 ± 3.8 seconds, 22.7 ± 11.8 and 20.6 ± 12.5 mm, respectively. The vocational change was significant for all parameters in the computer user group but not in the control group. The osmolarity-based dry eye diagnosis was 27.4% in the computer users while it was 15.4% in the control group. Oxford score was only grade 1 in 5.9% of visual display terminal users and did not change at the end of the day. Both symptoms and signs of dry eye increased significantly with computer use. Approximately 1 of every 3-4 computer users was found to have dry eye with higher tear osmolarity values.

Alteration of tear mucin 5AC in office workers using visual display terminals: The Osaka Study.

There are limited reports on the relationship between mucin 5AC (MUC5AC) concentrations in tears, working hours, and the frequency of ocular symptoms in visual display terminal (VDT) users. This investigation evaluated these relationships among patients with dry eye disease (DED) and individuals serving as controls. To determine the relationship between MUC5AC concentration in the tears of VDT users based on the diagnosis of DED and frequency of ocular symptoms. An institutional, cross-sectional study was conducted. Participants included 96 young and middle-aged Japanese office workers. Both eyes of 96 volunteers (60 men and 36 women) were studied. Participants working in a company that used VDTs completed questionnaires about their working hours and the frequency of ocular symptoms. Dry eye disease was diagnosed as definite or probable, or it was not present. Tear fluid was collected from the inferior fornix after instillation of 50 μL of sterilized saline. The MUC5AC concentration was normalized to tear protein content and expressed as MUC5AC (nanograms) per tear protein (milligrams). The differences in MUC5AC concentration between DED groups, between VDT working hours (short, intermediate, and long), and between symptomatic and asymptomatic groups were evaluated with 95% CIs based on nonparametric Hodges-Lehmann determination. Ocular surface evaluation, prevalence of DED, and MUC5AC concentration. The prevalence of definite and probable DED was 9% (n = 9) and 57% (n = 55), respectively. The mean MUC5AC concentration was lower in the tears of VDT users with definite DED than in those with no DED (P = .02; Hodges-Lehmann estimator, -2.17; 95% CI, -4.67 to -0.30). The mean MUC5AC concentration in tears was lower in the group that worked longer hours than in the group that worked shorter hours (P = .049; estimated difference, -1.65; 95% CI, -3.12 to 0.00). Furthermore, MUC5AC concentration was lower in participants with symptomatic eye strain than in asymptomatic individuals (P = .001; estimated difference, -1.71; 95% CI, -2.86 to -0.63). The data obtained in the present study suggest that office workers with prolonged VDT use, as well as those with an increased frequency of eye strain, have a low MUC5AC concentration in their tears. Furthermore, MUC5AC concentration in the tears of patients with DED may be lower than that in individuals without DED.

A Study of Musculoskeletal Disorders among Visual Display Terminal Workers

This study investigated the effectiveness of workstation ergonomic intervention in reducing musculoskeletal disorders (MSD) in Visual Display Terminal (VDT) workers. The study was carried out at one of a Multinational Company in Petaling Jaya, Selangor. Sixty Heavy VDT workers were selected randomly as case study respondents. Questionnaires were given to 60 respondents to investigate their awareness in ergonomic intervention, job-related factors that contributing to musculoskeletal disorders, as well as MSD severity and symptoms among them. Then, 30 workers who are heavy VDT users were selected to receive the education and ergonomics interventions, whereas another 30 receive the education and ergonomic intervention, whereas another 30 workers were assigned as a control group. The two groups were then crossedover after sixth week, and follow-up questionnaire s we given to all of them once again. The results for both questionnaires, before and after the ergonomics intervention, were then analyzed for this case study. The interventions include ergonomics leaflets, ergonomic posters, online ergonomic education and ergonomic working posture guidance. The outcomes suggested that a participation in an ergonomics program, even though in a short duration and minimally disruptive to the normal workplace routine, can still contribute to a rapid effect on improving work posture. Although improper posture is associated to be the main risk factor for work-related musculoskeletal disorders, multigroup and long-term randomized trial are required to establish the effectiveness or workstation ergonomic intervention in reducing musculoskeletal disorders in VDT workers. In conclusion, there is significant evidence that individualized ergonomic interventions may contribute to improve work-related posture and reduce MSD injuries for VDT workers.

Prevalence of Dry Eye Disease and its Risk Factors in Visual Display Terminal Users: The Osaka Study

To investigate tear function and prevalence of dry eye disease (DED) in visual display terminal (VDT) users. Cross-sectional study. Six hundred and seventy-two young and middle-aged Japanese office workers who used VDT completed questionnaires and underwent dry eye testing. We estimated the prevalence of DED using logistic regression analysis to examine associations between DED and possible risk factors. The ocular surface feature, prevalence of DED, and risk factors were evaluated. Of the 672 workers, 561 (83.5%, mean age: 43.3 ± 9.1 years) completed the questionnaire. The percentage of women with a composite outcome of definite DED or probable DED was 76.5%, which was higher than that among men (60.2%; odds ratio [OR] = 2.00; 95% confidence interval [CI], 1.29-3.10, P = .002). Workers over 30 years of age had a higher risk of DED (OR = 2.22; 95% CI, 1.06-4.66), as did workers using a VDT >8 hours per day (OR = 1.94; 95% CI, 1.22-3.09). Average Schirmer value was 18.7 ± 11.7 mm and tear break-up time (TBUT) was 4.0 ± 2.5 seconds (78.6% of study participants had TBUT ≤5 seconds). DED is prevalent among young to middle-aged Japanese VDT users. Ophthalmic findings revealed short TBUT and corneal staining accompanied by normal Schirmer test values. Increased risk for DED was noted for women aged over 30 years and prolonged VDT use. Measures to modify the adverse impact of VDT use on the ocular surface may provide a positive impact on public health and quality of life for office workers using VDTs.

Accumulation of Secretory Vesicles in the Lacrimal Gland Epithelia Is Related to Non-Sjögren's Type Dry Eye in Visual Display Terminal Users

Previous observations in a rat model of a non-Sjögren's syndrome (non-SS) type of dry eye seen in users of visual display terminals (VDT) indicated that secretory vesicle (SV) accumulation in the lacrimal gland epithelia contributes to the condition. Here, to examine this possibility in humans, we compared the lacrimal gland histology and percent SV area in the cytoplasm of acinar epithelial cells using light microscopy and transmission electron microscopy, in patients with VDT work-related non-SS dry-eye (VDT group), SS-induced dry-eye, and autopsied normal controls. In addition, the VAMP8 (vesicle-associated membrane protein 8, an exocrine-pathway molecule) and Rab3D (mature vesicle marker) were histochemically examined in lacrimal gland tissue sections. The lacrimal gland acini were larger in the VDT group than in the SS group, and the percent SV area was significantly higher in the VDT group than in the normal controls (P = 0.021) or SS group (P = 0.004). Immunostaining revealed abnormal distributions of VAMP8 in the VDT and SS groups. Rab3D was more strongly expressed in the cytoplasm of acinar epithelial cells in the VDT group than in that of normal controls. The duration of VDT use was significantly longer in the VDT group than in the other groups. These findings suggest that excessive SV accumulation in the acinar epithelia may contribute to the reduced tear secretion in VDT users.

Improvement of accommodation with anti-oxidant supplementation in visual display terminal users.

To determine the antioxidant supplementation effect on accommodation among VDT users. A double blind randomized placebo controlled study. Registered under ClinicalTrials.gov Identifier No. NCT00877201. Fourty right eyes of 40 healthy VDT users (30 females, 10 males, mean age: 43.8±2.8 years, range: 40-49 years). 20 subjects (15 females, 5 males; mean age: 44.0±2.7 years, range: 40-49 years). Subjects were required to take an antioxidant supplement, 20 age and sex matched subjects (15 females, 5 males; mean age: 43.6±3.1 years, range: 40-49 years) were required to take placebo medication for 4 weeks. The mean of the change in accommodation power was significantly higher in the group receiving antioxidant supplements (0.20±0.50 Diopter(D)) compared to the placebo group (-0.12±0.48(D)) (p<0.05). Antioxidant supplementation was observed to improve accommodation in Japanese Visual Display Terminal (VDT) Users.

Blink Rate, Blink Amplitude, and Tear Film Integrity during Dynamic Visual Display Terminal Tasks

Purpose: The present study aimed at investigating the influence of the level of dynamism of two different visual display terminal tasks on spontaneous eyeblink rate, blink amplitude, and tear film integrity.Material and Methods: A total of 25 healthy, young volunteers participated in the study. Blink rate and blink amplitude were recorded in silent primary gaze conditions and while subjects were playing two computer games of similar cognitive demands but different rate of visual information presentation. For each experimental condition, tear volume was evaluated by measuring meniscus height and with the red phenol thread test. Fluorescein and non-invasive break-up time tests, as well as the observation of interference patterns and the estimation of the dry area extension, were employed to assess tear stability.Results: Statistically significant differences were revealed in blink rate (F = 595.85, p < 0.001) and blink amplitude (χ2 = 34.00, p < 0.001), with blink rate during fast- and slow-paced game play decreasing to almost 1/3 and 1/2 of baseline levels, respectively, and with a larger percentage of incomplete blinks during dynamic tasks. Fluorescein and non-invasive break-up time tests and dry area extension were able to differentiate between experimental conditions in general (F = 408.42, p < 0.001; F = 163.49, p < 0.001; χ2 = 20.74, p < 0.001), as well as between fast- and slow-paced games, thus suggesting that tear quality was more affected than tear volume.Conclusions: Blink rate, blink amplitude, and tear film stability were compromised during the most dynamic visual display terminal task, suggesting a negative influence of not only the cognitive aspects of the task, but also of the rate at which new visual information is presented. Frequent breaks and blinking awareness training are recommended for visual display terminal users requiring prolonged periods of visually demanding dynamic computer play or work.

An online tool to identify white-collar worker profiles in relation to their ICT skills and mental strain

The introduction of Internet and Information and communication Technologies (ICT) in offices is a global phenomenon that transformed white-collar worker job demands. Although there are several studies of e-skills and mental workload for central countries, there is a lack of similar studies for the Latin American context. An online snowball sampled (n = 352) survey was developed and validated by the authors (internal consistency = 0.7). We characterized ICT worker profiles from e-skills and these dimensions: attitudes toward, resources usage and technology dependency. Mental Strain was assessed with raw task load index (RTLX) and correlated with the proposed profiles by means of paired T-tests and Mann–Whitney Tests. The sample was characterized by 7.2% of non visual display terminal users and 92.8% of visual display terminal, ICT skilled users. Of the latter, 30.7% were ICT practitioners, 30.4% were ICT Users and 27.2% were E-Business Users. Non VDT users’ mental strain was statistically meaningful smaller than VDT–ICT skilled users’ mental workload. No statistical differences were found in RTLX results when comparing ICT skilled user profiles. Non VDT users can be identified from ICT skilled Users by their lower ITC Dependency and minor use of ICT resources. There were no differences in those dimensions among ICT skilled Profiles. Attitude toward these technologies was a distinct factor for ICT Users in relation to ICT Practitioners and ITC Business Users. The application of this tool in peripheral and central countries would allow a complete ergonomical characterization of white-collar workers within the Information Society.

Lacrimal Hypofunction as a New Mechanism of Dry Eye in Visual Display Terminal Users

BackgroundDry eye has shown a marked increase due to visual display terminal (VDT) use. It remains unclear whether reduced blinking while focusing can have a direct deleterious impact on the lacrimal gland function. To address this issue that potentially affects the life quality, we conducted a large-scale epidemiological study of VDT users and an animal study.Methodology/Principal FindingsCross sectional survey carried out in Japan. A total of 1025 office workers who use VDT were enrolled. The association between VDT work duration and changes in tear film status, precorneal tear stability, lipid layer status and tear secretion were analyzed. For the animal model study, the rat VDT user model, placing rats onto a balance swing in combination with exposure to an evaporative environment was used to analyze lacrimal gland function. There was no positive relationship between VDT working duration and change in tear film stability and lipid layer status. The odds ratio for decrease in Schirmer score, index of tear secretion, were significantly increased with VDT working year (P = 0.012) and time (P = 0.005). The rat VDT user model, showed chronic reduction of tear secretion and was accompanied by an impairment of the lacrimal gland function and morphology. This dysfunction was recovered when rats were moved to resting conditions without the swing.Conclusions/SignificanceThese data suggest that lacrimal gland hypofunction is associated with VDT use and may be a critical mechanism for VDT-associated dry eye. We believe this to be the first mechanistic link to the pathogenesis of dry eye in office workers.

Asthenopia and Use of Glasses among Visual Display Terminal (VDT) Users

Asthenopia and Use of Glasses among Visual Display Terminal (VDT) Users

Prevalence of Dry Eye Disease among Japanese Visual Display Terminal Users

To determine the prevalence of dry eye disease (DED) and risk factors among young and middle-aged Japanese office workers using visual display terminals (VDTs). Cross-sectional prevalence survey. Four thousand three hundred ninety-three Japanese young and middle-aged office workers using VDTs. Office workers completed questionnaires sent by e-mail designed to detect dry eye diagnosis and risk factors. Clinically diagnosed DED was defined as the presence of a previous clinical diagnosis of DED by dry eye specialists or severe symptoms of DED (both dryness and irritation constantly or often). Current symptoms of DED and possible risk factors such as age, duration of VDT use, type of VDT work, environmental factors, presence of systemic diseases, systemic medicine use, smoking history, and contact lens (CL) use were the main outcome measures. We used logistic regression to examine associations between DED and other demographic factors. Of the 4393 office workers, 3549 (80.1%) completed the questionnaire. Clinically diagnosed DED was present in 266 (10.1%) of 2640 male subjects and in 195 (21.5%) of 909 female subjects. Severe symptoms of DED were observed in 711 male and in 436 female participants. More than 4 hours of VDT use was associated with an increased risk of DED (odds ratio [OR], 1.68; 95% confidence interval [CI], 1.40-2.02). In addition, CL use (OR, 3.91; 95% CI, 3.37-4.53) increased the risk of severe dry eye symptoms. Dry eye disease leading to a clinical diagnosis or severe symptoms is prevalent among young and middle-aged Japanese office workers. The condition is more prevalent among females, CL wearers, and prolonged VDT users. Relevant measures directed against the modifiable risks could provide a positive impact on public health and quality of life of office workers. The authors have no proprietary or commercial interest in any materials discussed in this article.

Influence of Work Duration or Physical Symptoms on Mental Health among Japanese Visual Display Terminal Users

The present study examined the relationship of work duration or physical symptoms to the mental health of visual display terminal (VDT) workers in Japan. The mental health status of 2,327 VDT users at an administrative office was investigated using the 12-item General Health Questionnaire (GHQ-12). Subjects were asked about their age, sex, hours of daily VDT use, rest and breaks during VDT work, eyestrain, and musculoskeletal pain. Logistic regression analysis was used to evaluate the associations with mental health status (GHQ-12 scores). The mean age of subjects was 39.5 yr (SD=10.3). Among all subjects, 36.7% could rest during VDT work and 66.9% received breaks during VDT work. The proportion of subjects who reported eyestrain and musculoskeletal pain were 19.6% and 25.7%, respectively. Eighteen percent of subjects were classified into a GHQ-12 high score group. Logistic regression analysis showed that age less than 40 yr, not receiving breaks during VDT work, and the presence of eyestrain and musculoskeletal pain were significantly associated with poor mental health status (high GHQ-12 scores). Using a VDT for more than 5 h/d and being female were also marginally associated with high GHQ scores (p<0.1). In conclusion, the management of physical health as well as work duration is important for good mental health status among VDT users.

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.

Analytic and rule-based decision support tool for VDT workstation adjustment and computer accessories arrangement.

One important factor that leads to the development of musculoskeletal disorders (MSD) and cumulative trauma disorders (CTD) among visual display terminal (VDT) users is their work posture. While operating a VDT, a user's body posture is strongly influenced by the task, VDT workstation settings, and layout of computer accessories. This paper presents an analytic and rule-based decision support tool called EQ-DeX (an ergonomics and quantitative design expert system) that is developed to provide valid and practical recommendations regarding the adjustment of a VDT workstation and the arrangement of computer accessories. The paper explains the structure and components of EQ-DeX, input data, rules, and adjustment and arrangement algorithms. From input information such as gender, age, body height, task, etc., EQ-DeX uses analytic and rule-based algorithms to estimate quantitative settings of a computer table and a chair, as well as locations of computer accessories such as monitor, document holder, keyboard, and mouse. With the input and output screens that are designed using the concept of usability, the interactions between the user and EQ-DeX are convenient. Examples are also presented to demonstrate the recommendations generated by EQ-DeX.

Physical Discomfort Among Visual Display Terminal Users in a Semiconductor Manufacturing Company: A Study of Prevalence and Relation to Psychosocial and Physical/Ergonomic Factors

The associations among several alleged psychosocial and physical/ergonomics risk factors and the visual and musculoskeletal discomforts were assessed in a cross-sectional study of 119 video display terminal (VDT) users in a semiconductor manufacturing company. Cases of discomfort were identified using self-reported discomfort symptoms through questionnaire surveys. Data on individual, physical/ergonomic, and psychosocial aspects were obtained. Multivariate logistic regression models were developed to predict physical discomforts of 11 body areas. The prevalence of upper extremity discomfort found in this semiconductor manufacturing company was 42%, which is similar to the prevalence among VDT users in telecommunication companies and the newspaper industry. Full-time VDT users (data-entry personnel, programming engineers, and CAD engineers) had significantly higher rates of physical discomfort (66%) than part-time VDT users (fabrication engineers) (41%). Physical/ergonomic variables were found more dominant than psychosocial factors for visual and upper extremity discomforts. However, psychosocial variables were the dominant for back and lower extremity discomfort, when compared with the subjectively characterized physical/ergonomic factors. Because both physical/ergonomics variables and psychosocial factors and some of their interactions were associated with visual and musculoskeletal discomfort, integrating psychosocial prevention with physical/ergonomic design improvements is an effective approach to reducing the prevalence of discomfort.

Physical Discomfort Among Visual Display Terminal Users in a Semiconductor Manufacturing Company: A Study of Prevalence and Relation to Psychosocial and Physical/Ergonomic Factors

Physical Discomfort Among Visual Display Terminal Users in a Semiconductor Manufacturing Company: A Study of Prevalence and Relation to Psychosocial and Physical/Ergonomic Factors

An Attempt at Preventing Asthenopia Among VDT Workers

We report the results of 3 surveys of visual display terminal (VDT) users who took a minibreak during which they viewed a stereoscopic image of a repeating parallel pattern showing planets. The single image stereogram method employed is called Stretch EyeTM, and we evaluated the effects of Stretch EyeTM on asthenopia. An accommodative relaxation of about 1 D was observed in participants while they were gazing at the image. The employees of 2 information technology companies were evaluated according to a visual analogue scale (VAS) for subjective symptoms of asthenopia and eyesight. The results showed that Stretch EyeTM was effective in easing visual fatigue due to VDT work and it improved eyesight under working conditions.

Visual Strain and Lighting Preferences of VDT Users Under Different Lighting Systems

Lighting influences users’ visual strain and well-being. Therefore creating lighting that ensures visual work conditions do not result in visual fatigue is a preventive activity. The aim of the study was to model different lighting systems for visual display terminal (VDT) work and to determine their influence on users’ visual strain and preferences. The results of the study showed that visual fatigue was lowest for indirect and compound lighting systems. On the other hand, in general, direct lighting realized by “dark-light” luminaires was the most preferred lighting system. Some interesting differences related to age, gender, and VDT work experience were found. On the basis of the obtained results lighting designers can be provided with some guidance.