Visual Display Terminal Work Research Articles

Safety and Efficacy of Photocatalytic Micro-Mist Desktop Humidifier for Dry Eye Caused by Digital Environment: A Randomized Controlled Trial.

Background/Objectives: Modern life is inconceivable without visual display terminal (VDT) work, including smartphones, computers, and games for both children and adults. VDT work under air conditioning and low humidity poses a high risk of dry eye and digital eye strain. Methods: Thirty-one participants were randomly divided into two groups using a desktop humidifier with photocatalytic technology, namely the "with mist" (humidifier) group and "without mist" (control) group. Participants performed VDT tasks using the humidifier with or without mist for 1 h. Ocular subjective symptoms and objective tear film parameters were assessed before, immediately after, and 1.5 h after the VDT task with or without mist. (Registry ID: UMIN000054379) Results: Ocular symptom scores improved significantly in the humidifier group immediately after the VDT task and up to 1.5 h later compared to before the task (p < 0.001, =0.006, respectively). Immediately after the VDT task, tear meniscus height was significantly higher and non-invasive breakup time was significantly longer in the humidifier group than in the control group (p < 0.001, =0.040, respectively). Plugging of the meibomian gland orifices was significantly reduced only in the humidifier group immediately after the VDT task compared to before the VDT task and remained significantly reduced up to 1.5 h later (p = 0.004, 0.016, respectively). Conclusions: The use of the photocatalytic desktop humidifier during VDT task resulted in significant improvements in the tear film parameters and subjective symptoms. The photocatalytic desktop humidifier could be effective in alleviating dry eye and eye strain in computer users in a modern office environment.

Identification Of Dry Eye Syndrome Risk Factors In Workers Who Use Visual Display Terminals (VDT)

Dry eye syndrome is a multifactorial disease of the eye air and eye surface which causes symptoms of discomfort, visual disturbances, and instability of the eye air layer which has the potential to damage the eye surface. This condition has an impact on productivity, activities in the work environment, apart from that it also has an impact on lower employment opportunities, decreased working hours and increases a person's inability to work. Using visual display terminals for 5-7 hours/day can significantly increase the incidence of dry eye syndrome. Therefore, paying attention to the risk factors of visual display terminal workers is very important in preventing the occurrence of dry eye syndrome. The research method uses literature studies from several national and international journals obtained from 18 reference sources through searches on PubMed and Google Scholar published in the last 5 years. There were 18 articles with full text that met the inclusion criteria and contained several risk factors associated with the incidence of dry eye syndrome. Risk factors for dry eye syndrome in workers who use visual display terminals include age, gender, screen exposure time, psychological stress, work environment, use of contact lenses, use of drugs and history of surgery, refractive disorders, and length of work. Identification of risk factors for dry eye syndrome in workers who use visual display terminals can reduce the incidence and morbidity associated with this disease. So it can improve the quality of life of workers

Association of ocular surface and meibomian gland alterations with silicone hydrogel contact lens wear

PurposeTo evaluate silicone hydrogel contact lens (SH-CL) effects on the meibomian glands, corneal structure, and ocular surface parameters. MethodsFifty SH-CL wearers for at least 6 months, and 50 sex and age-matched control subjects were recruited for this cross-sectional study. Visual display terminal (VDT) work and CL wear duration were questioned, ocular surface and tear functions were evaluated using OSDI questionnaire, tear break-up time (TBUT), corneal fluorescein staining, and Schirmer test. Corneal sensitivity was measured with Cochet-Bonnet aesthesiometry. Meibography and in vivo confocal microscopy (IVCM) were performed to evaluate meibomian glands and corneal structure. Intergroup comparisons were made using the Chi-square test, Wilcoxon test, or Kruskal–Wallis test. ResultsIn the CL group, TBUT was shorter (P = 0.01), corneal fluorescein staining (P = 0.04), OSDI scores (P < 0.001), and meiboscores (P < 0.001) were higher than the control group. The biomicroscopic evaluation revealed meibomian gland dysfunction (MGD) in 34 % of the CL group and 20 % of the control group, which was not statistically significant (P > 0.05). IVCM showed that endothelial cell density was lower (P = 0.01) and polymegethism was higher (P < 0.001) in the CL group. Subbasal nerve density and corneal sensitivity measurements were similar in the two groups (P > 0.05). The longer VDT work duration was associated with increased CFS in the CL group (P = 0.05). ConclusionThe results showed that SH-CL wear increased dry eye symptoms and ocular discomfort, especially in longer VDT work duration. Meibography revealed significantly worse results in SH-CL wearers. SH-CL-related ocular discomfort seems to be more associated with MGD rather than neurosensorial alterations.

Relationship between visual display terminal working hours and headache/eyestrain in Korean wage workers during the COVID-19 pandemic: the sixth Korean Working Conditions Survey.

Prolonged use of visual display terminal (VDT) can cause eyestrain, dry eyes, blurred vision, double vision, headache and musculoskeletal symptoms (neck, shoulder, and wrist pain). VDT working hours among workers have greatly increased during the coronavirus disease 2019 (COVID-19) pandemic. Therefore, this study aimed to investigate the relationship between VDT working hours and headache/eyestrain in wage workers using data from the sixth Korean Working Conditions Survey (KWCS) (2020-2021) conducted during the COVID-19 pandemic. We analyzed the sixth KWCS data of 28,442 wage workers aged 15 years or older. The headache/eyestrain that occurred in the last year was assessed. The VDT work group included workers who use VDT always, almost always, and three-fourth of the working hours, while the non-VDT work group included workers who use VDT half of the working hours, one-fourth of the working hours, almost never, and never. To analyze the relationship between VDT working hours and headache/eyestrain, the odds ratios (ORs) and 95% confidence interval (CI) were calculated using logistic regression analysis. Among the non-VDT work group, 14.4% workers experienced headache/eyestrain, whereas 27.5% workers of the VDT work group experienced these symptoms. For headache/eyestrain, the VDT work group showed adjusted OR of 1.94 (95% CI: 1.80-2.09), compared with the non-VDT work group, and the group that always used VDT showed adjusted OR of 2.54 (95% CI: 2.26-2.86), compared with the group that never used VDT. This study suggests that during the COVID-19 pandemic, as VDT working hours increased, the risk of headache/eyestrain increased for Korean wage workers.

Effects of diet containing astaxanthin on visual function in healthy individuals: a randomized, double-blind, placebo-controlled, parallel study.

Visual display terminal work has increased rapidly in recent years. Loss of visual acuity is an unfortunate associated effect. Here, we performed a randomized, placebo-controlled study in 60 healthy adults. Participants received a diet containing astaxanthin (9 mg/day) or placebo for 6 weeks. Visual acuity, functional visual acuity, and pupil constriction rate were measured before and after visual display terminal work. In participants aged ≥40 years, corrected visual acuity of the dominant eye after visual display terminal work at 6 weeks after intake demonstrated a higher protective effect of astaxanthin in the astaxanthin group vs the control group (p<0.05). In participants aged <40 years, no significant difference was seen between the astaxanthin and control groups. Moreover, no significant difference was found in functional visual acuity and pupil constriction rate between the astaxanthin and control groups. These results suggest astaxanthin reduces oxidative stress caused by visual display terminal work. Age-related reduction in ciliary muscle strength is likely the main detractor of visual acuity. Correspondingly, astaxanthin reduced visual display terminal work-induced visual stress in the middle-aged and elderly. This study was registered in the UMIN-CTR database (UMIN000043089).

The relationship between visual display terminal usage at work and symptoms related to computer vision syndrome.

Although it is well known that the usage of visual display terminal (VDT) at the workplace causes computer vision syndrome (CVS), previous studies mainly focused on computer use and the health of white-collar workers. In this study, we explored the relationship between the usage of VDT including various devices, and symptoms related to CVS in a large population including pink-collar workers and blue-collar workers. 21,304 wage workers over the age of 20 years were analyzed from the 6th Korean Working Conditions Survey. To investigate the association between VDT use at work and symptoms related to CVS among wage workers, odds ratios (ORs) and 95% confidence interval (CI) were calculated by multivariate logistic regression models. In the group with the highest VDT usage at work, the OR of headache/eyestrain was 2.16 (95% CI: 1.86-2.52). The OR of suspected CVS patients was significantly increased in the highest group of usage of VDT at work (OR: 1.69; 95% CI, 1.39-2.06). Compare with the reference group, the OR for headache/eyestrain in the highest group of VDT usage was 2.81 (95% CI: 2.13-3.70) in white-collar workers, 1.78 (95% CI: 1.32-2.40) in pink-collar workers, and 1.59 (95% CI: 1.18-2.15) in blue-collar workers. We observed a relationship in which the use of VDT in the workplace increases the risk of headache/eyestrain regardless of occupational classification. Our findings emphasize the importance of paying attention to the health of VDT workers and making plans to improve their working conditions.

Effects of a Traction Device for Head Weight Reduction and Neutral Alignment during Sedentary Visual Display Terminal (VDT) Work on Postural Alignment, Muscle Properties, Hemodynamics, Preference, and Working Memory Performance.

The forward head posture of visual display terminal (VDT) users induces various physical and cognitive clinical symptoms. However, few studies have been conducted to identify and solve problems associated with VDT posture. This study aimed to examine the adverse effects of VDT posture and the positive effects of traction-combined workstations by measuring postural alignment, muscle properties, blood velocity, preference, and working memory. Thirty-four healthy VDT users (18 males and 16 females aged 20-30 years) participated in the experiment at three workstations, including conventional (VDT_C), head support (VDT_S), and upright (VDT_U) workstations. They conducted 2-back working memory task. The craniovertebral angle (CVA), muscle tone and stiffness, blood velocity and visual analogue discomfort scale (VADS) were measured to examine the influence of workstations. VDT_C showed increased muscle tone or stiffness in the levator scapulae (LS), suboccipital muscle (SM), and sternocleidomastoid muscle (SCM) and an increased reaction time (RT) in working memory. However, VDT_S showed decreased stiffness and tone of SM and improved comfort. In addition, VDT_U showed decreased stiffness or tone of the LS and SCM and improved blood velocity and RT. In conclusion, maintaining neutral alignment significantly improved working memory performance, muscle properties, and blood velocity.

Umor očiju korisnika terminala za videoprikaz i njegov odnos s poremećajima spavanja

Visual display terminal (VDT) work has become a major part of operation in majority of workplace. This study aimed to eye fatigue in video display terminal users and its relation to sleep disorders. This cross-sectional study was done on 209 computer users who work more than one year in this field. All participants completed a questionnaire about their age, sex, BMI, years of experience, and hours of daily computer use. A standardized visual fatigue questionnaire was used for detection presence and severity of eye strain. Sleep quality was used to assess Pittsburg Sleep Quality Questionnaire (PSQI) , and the Epworth Sleepiness Questionnaire (ESS) to assess daytime sleepiness in participants. Insomnia was assessed by Insomnia Severity Index (ISI). The most common eye symptoms including eye fatigue (65.5%), eyelid heaviness sensation (69.4%), eye irritation (67.2%), dry eye (67.8%), blurred vision (68.5%), and tearing (68.1%) were significantly higher in participants who were working more than 8 hours with DVT in day. There was a significant correlation between scores of eye fatigue and insomnia severity (Rho=0.32, P&lt;0.05). According to results, the prevalence of eye symptoms particularly eyelid heaviness sensation and blurred vision was high. However, eye fatigue was more affected insomnia severity in VDT users. Therefore, it is needed to protect computer users from the adverse effects of VDT. Implementing proper ergonomic programs to the workplace are important for achievement to good physical and mental health among VDT users.

An Investigation of the Effects of Brain Fatigue on the Sustained Attention of Intelligent Coal Mine VDT Operators.

Intelligent mines require much more mental effort from visual display terminal (VDT) operators. Long periods of mental effort can easily result in operator fatigue, which further increases the possibility of operation error. Therefore, research into how brain fatigue affects the sustained attention of VDT operators in intelligent mines is important. The research methods were as follows: (1) Recruit 17 intelligent mine VDT operators as subjects. Select objective physiological indicators, such as reaction time, error rate, task duration, flicker fusion frequency, heart rate, electrodermal activity, and blink frequency, and combine these with the subjective Karolinska Sleepiness Scale to build a comprehensive brain fatigue evaluation system. (2) According to the fatigue-inducing experiment requirements, subjects are required to carry out mathematical operations in accordance with the rules during the presentation time, determine whether the results of the operations fall within the [7, 13] interval, and continue for 120 min to induce brain fatigue. (3) Perform the standard stimulus button response experiment of the sustained attention to response task, before and after brain fatigue, and compare each result. The results show that: (1) When the standard stimulus appeared in the EEG experiment, the amplitude of the early N100 component before and after brain fatigue was significantly different. When the bias stimulus appeared, the average amplitudes of the P200 component and the late positive component, before and after brain fatigue, were significantly different, suggesting that the brain fatigue of VDT workers in coal mines would reduce sustained attention; (2) After the 120 min of the continuous operation task, the subjects showed obvious brain fatigue. The objective brain fatigue was followed by an increase in reaction time, an increase in error rate, a decrease in flicker fusion frequency, an increase in heart rate, an increase in electrodermal current, an increase in the number of blinks, and a larger pupil diameter, and both the subjective and objective data indicated more significant changes in the subjects’ brain fatigue at the 45th and 90th min. The results of the study could provide insight into the reduction in operational efficiency and safety of VDT operators in intelligent mines due to brain fatigue and further enrich the research in the area of brain fatigue in VDT operations.

The association between visual display terminal use and dry eye: a review.

Dry eye disease (DED) is a multifactorial disease of the tear film and ocular surface. It causes ocular symptoms, reduced quality of life and a considerable economic burden on society. Prolonged use of visual display terminals (VDTs) has been suggested as an important risk factor for DED. This review aims to study the association between DED and VDT use with an emphasis on the prevalence of DED among VDT users and harmful daily duration of VDT use. A PubMed search was conducted and yielded 57 relevant articles based on a set of inclusion and exclusion criteria. The studies were subclassified according to study design. The far majority of the studies showed an association between VDT use and DED or DED-related signs and symptoms. The prevalence of definite or probable DED in VDT and office workers ranged from 26% to 70%, with as few as 1-2 hr of VDT exposure per day being associated with DED. VDT use is strongly associated with DED. VDT-associated DED is prevalent, but the exact prevalence needs to be further elucidated using standardized DED diagnosis criteria. Furthermore, a safe lower limit of daily VDT use has yet to be established. More research is needed on the effect of digitalization and digital transformation, which are particularly high during the time of the COVID-19 pandemic.

Effects of Resistance Footrest on Spine Posture in Visual Display Terminal Workers

Background: Flat-back posture refers to a posture in which the pelvis is tilted backward, the lumbar spine is bent, the upper thoracic spine is increasingly bent, and the lower thoracic spine is straight. Given that most of the day is spent sitting, we need to develop exercise programs and devices that are suitable for people who spend less time exercising than sitting. Objects: This study investigated the effects of resistance footrest exercise on spine posture angles in visual display terminal (VDT) workers with flat back. Methods: We measured the upper lumbar angle (ULA) and lower lumbar angle (LLA) using a flexible ruler for the ULA and LLA. Then, after 1 week of resistance footrest exercise designed to strengthen the lumbar spine musculature, we measured these angles again. We measured each angle three times and then compared measurements from before and after exercise. Results: There were no significant differences in the ULA following the strengthening exercise, but significant differences were observed in LLA. Conclusion: The resistance footrest exercise strengthened the muscles affecting the pelvic and lumbar lordotic angles, and increases in the LLA were changed. This suggests that the role of the lower lumbar spine in the lumbar lordotic curve is greater than that of the upper lumbar spine. In addition, considering the contemporary tendency to lead fairly sedentary lives, these results indicate that exercising while seated can be effective.

An exploratory study on the impact of static and dynamic sitting postures on lumbar and pelvic mobility during visual display terminal work.

[Purpose] Limited studies exist on the impact of sustained work at a visual display terminal (VDT) on the position and motion of the pelvis and lumbar spine. We evaluated the changes in movement of the lumbar column and pelvis during VDT work. [Participants and Methods] We evaluated the sitting posture of 20 healthy adults while they performed VDT work. The effects of the sitting posture on lumbo-pelvic position and motion were captured using a three-dimensional accelerometer. Between-posture effects of VDT work were evaluated using an analysis of variance (ANOVA). A two-way ANOVA was used to assess the root mean square (RMS) values of the 80-min VDT work period for each posture. A one-way ANOVA was used to evaluate pre- and post-work changes in RMS values during the finger floor distance test (FFD). [Results] People in the dynamic sitting balance chair (DSBC)-based posture demonstrated significantly higher pelvic RMS values than those in reclining and upright sitting postures. The DSBC-based posture was also associated with significantly higher pre- and post-work lumbar and pelvic RMS values during the FFD than in the reclining and upright sitting postures. [Conclusion] The dynamic balance chair may be an effective method of establishing a pattern of spinal exercise during prolonged sitting.

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.

How Optimal is The Visual Display Terminal (VDT) Work Station at The Public Health Faculty, Universitas Airlangga

Introduction: The academic and student affairs department in the administration room of the Faculty of Public Health of Universitas Airlangga works using a Visual Display Terminal (VDT) with a sitting work position that has the potential to cause eye strain and several muscular disorders. This study aimed to describe the work station of VDT users in the administration room of the Public Health Faculty, Universitas Airlangga. Method: This research was an observational research using cross-sectional descriptive design. The population was the users of the VDT in the administration room of the Public Health Faculty, Universitas Airlangga, as many as 11 people. The sample used was total population. Data were collected using an observation sheet and then was analyzed descriptively. Result: The head position of all workers were optimal (100.0%); the majority of workers' visibility was optimal (54.5%); all table heights were optimal (100.0%); most of the elbow angel and keyboard position was not optimal (63.6%); the majority of mouse positions were optimal (54.5%); chair heights were not optimal (100.0%); most of the backrest and waist angle was optimal (72.7%); most of the workers' knee angles were not optimal (81.8%); most of the legroom were optimal (81.8%); all workstations did not have footing and document holders (100.0%), so they were considered not optimal. Conclusion: Most of the elements is considered as optimal, but some elements are not optimal, including elbow angle, the keyboard position, chair height, knee angle, footing, and document holder.Keywords: work station, sitting work position, visual display terminal

Ocular symptoms survey among undergraduate students in this COVID-19 era

AIM: To find out ocular symptoms in Visual Display Terminals (VDTs) users, among undergraduate students who adopted new education system in this COVID-19 era. Methods: A cross-sectional, observational survey carried out in the month of September 2020, which included undergraduate students from Ahmedabad, who were using Visual Display Terminals (VDTs) for educational activities for more than 6 to 8 months. A total of fourteen validated questionnaires were selected, webpage survey form was created and the link was sent via various social media platform. Responses were assessed in the scale of 0 to 4 (0= never, 1=infrequently, 2=sometimes, 3= often, 4=always). The percentage of symptoms was calculated in terms of subjects, also in the scale of 0 to 4.Results: A total of 103 undergraduate students responded with mean age of 19±1.5 years. Highest number (40: 4-6 hours, 36: 7-9 hours) of students had a screen time of 4 to 9 hours per day. The burning sensation (69.8%), redness (51.4%), itching (47.6%) were the most common symptoms, followed by irritation (34.6%), and scratchiness (25.5%) related to dry eyes. However, majority of the patients had those symptoms on infrequent duration. A loss of the concentration (73.8%), tired eyes (69.6%), discomfort (61.2%), headache (60.7%), reduced reading speed (56.3%), fluctuation in vision (44.7%), blurring (43.7%), were the most common symptoms related to the near work. Majority of participants felt these complain for the duration of infrequent to often basis. The double vision (25.2%) and floating of objects (11.7%) were the least common symptoms related to near work. Conclusion: The VDTs related symptoms are increasing in the students in this COVID-19 era. Increasing awareness, proper counselling regarding algorithm of VDTs, taking regular breaks, avoiding unnecessary web searching and social media can help to relieve or minizine symptoms related to VDTs work in this COVID-19 era.

Effect of blue light from LCD on VDT work: Experiment using blue light reduction function LCD

AbstractThe aim of this study was to examine the impact of the blue light from the visual display terminal (VDT) on visual search tasks. We assessed the quantity of the blue light from medical imaging diagnoses (medical‐grade) liquid‐crystal display (LCD) and general (personal computer‐grade) LCD for the VDT work, both equipped with the blue light reduction function. Then, we measured the visibility of display by evaluating the correct answer rate and reaction time of visual search tasks. The quantity of the blue light was proportional to the luminance of the display. When the blue light reduction function was used during the VDT work, the blue light at the peak wavelength was reduced by about 56%. Though the luminance of the display reduced, the visibility of the display was not decreased. These findings suggest that the blue light reduction on the LCD could work efficiently in the VDT work, maintaining the visibility of the display.

Analysis of the relationship between daylight illuminance and cognitive, affective and physiological changes in visual display terminal workers

This study explored the impact of daylight illuminance on cognitive load during visual display terminal use by means of various physiological, performance and subjective measures. Repeated-measures design was adopted to identify the impact of variations in daylight levels that were manipulated through the shading system configurations (shading-on; shading-off). A total of 30 subjects performed visual and cognitive demanding tests. Performance measures were supported by subjective data and eye-related measures during the experimental analysis. Results revealed that the use of a shading system had positive impact on sustained attention. Concerning ocular measures, percentage of eye closure values showed opposite tendencies among vigilance and sustained attention demanding tests. Eye aspect ratio-max and blink duration were significantly correlated with reported glare sensation. In all tests, eye aspect ratio-max was found significantly higher in lower illuminances. Search velocity was significantly correlated with ocular variables in higher illuminances whereas sustained attention showed an opposite trend. This, initially, explains that even slight differences in daylight illuminance might have distinctive effects on the relationship between different groups of assessment variables while measuring cognitive load. Secondly, it proves the significance of carrying out sensitive experiments in terms of both light levels and test characteristics. Practical application: The findings of this study could suggest that a practical application, the use of a shading device, might deliver an efficient solution on such a multifaceted question about the potential effects of luminous environment on the evaluation of cognitive load. Work environments might be considered as cognitively efficient if only the harmony of less mental effort, more satisfaction and less health problems exist, which together ultimately deliver higher work performance. In real-world work environments, application of such shading devices involves advantages not only for avoiding excessive daylight exposure or optimizing energy consumption, but also facilitating cognitive, affective and physiological processes of individuals.

Changes in Distribution of Dry Eye Diagnostic Status Among Visual Display Terminal Workers According to the Revised Criteria of the Asia Dry Eye Society.

The present study aimed to compare the prevalence of dry eye disease (DED) among visual display terminal users using the revised and previous DED criteria. This cross-sectional study included 561 participants (187 women). The distribution of diagnostic status according to the previous DED criteria was as follows: definite DED (n = 65, 11.6%), probable DED (n = 303, 54.0%), and non-DED (n = 193, 34.4%). According to the revised criteria, 329 participants (58.6%) were classified as DED and 232 participants (41.4%) were classified as non-DED. The prevalence of DED among visual display terminal users has increased to 58.6% from 11.6%, according to the revised DED diagnostic criteria of the Asia Dry Eye Society.

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.

Blind working time in visual display terminal users.

ObjectivesBlind working (BW) time (time during which vision is not required), the interblink interval (IBI), and subjective symptoms were investigated in workers using visual display terminals (VDTs).Subjects and MethodsTo investigate BW time, 10 VDT users were instructed to close their eyes when this did not interfere with their work. They were video recorded for 60 minutes using a webcam attached to the display on which they were engaged in regular data input tasks, and BW time was measured. The values of the IBI during the final 20 minutes of the BW experiment and during the final 20 minutes of normal working without BW were compared. A questionnaire was administered to investigate subjective symptoms using a visual analogue scale.ResultsThe total BW time during the final 20‐minute period was 20.6‐121.0 seconds (1.7%‐10.1%). The mean IBI of 5.5 ± 4.5 seconds during the BW experiment was not significantly different from that of 6.2 ± 5.6 seconds during normal working, and the mean of three IBIs immediately after BW during the BW experiment was 2.7 ± 1.0 seconds, significantly shorter than the 6.2 ± 5.6 seconds during normal working. Dry eye, ocular fatigue, and blurred vision during normal working improved when subjects were engaged in BW.ConclusionsVDT users could engage in BW during VDT work, the IBI was shorter immediately after BW, and subjective symptoms improved. These results suggest that BW may provide a more effective measure for the management of VDT working time.