Visual display terminal syndrome and its associated factors among university students during the COVID-19 pandemic

BACKGROUND

Ever since the start of the coronavirus disease 2019 (COVID-19) pandemic, students have been spending an increasingly longer time staring at electrical devices to take online courses.

OBJECTIVE

This study aimed to investigate the effect of the virtual class environment on eye and musculoskeletal problems in university students during the COVID-19 pandemic.

METHODS

A total of 365 university students were enrolled in this study. They completed an online survey to examine the effects of online learning on eye and musculoskeletal health during the COVID-19 pandemic. The questionnaires consisted of four sections: demographic and general information, environmental and work factors, device-related factors, and visual display terminal syndrome (VDTS).

RESULTS

Participants have been taking online classes of 14.5 hours per week during the COVID-19 pandemic. They reported the mean daily usage of digital devices of 4.8±2.2 hours before the pandemic but this increased to 8.1±2.9 during the pandemic. Eye fatigue and neck, shoulder, and back pain have also been reported. The mean VDTS score was significantly influenced by gender, obesity, daily exercise, regular breaks, wear of blue light-blocking glasses, daily hours of electronic device use, and illumination of room.

CONCLUSION

The results of this study showed that university students taking online classes suffered more from VDTS, especially in eye fatigue and neck, lower back, and shoulder pain during COVID-19 pandemic than prior. This study suggests that it is necessary to take breaks in online classes and regularly provide appropriate eye exercise and physical activity to prevent VDTS.

Prevalence and determinants of asthenopia among ophthalmologists in China: a national cross-sectional survey

Introduction

The role of ophthalmologists is defined by tasks requiring visual effort, emphasizing the importance of examining their condition within the realm of occupational visual health. Our goal was to explore the occurrence of asthenopia among Chinese ophthalmologists and identify contributing factors through the use of a reliable and validated survey instrument.

Methods

A national cross-sectional online survey was carried out in June 2017, involving 6,220 practicing ophthalmologists in China. Utilizing an 11-item Asthenopia Survey Questionnaire with established reliability and validity. Prevalence rates of asthenopia among subgroups categorized by age, gender, hospital classification, physician level, daily near vision activity duration, sleep duration, sleep quality, presbyopia status, and history of eye surgery were determined using the independent t-test, chi-square test and bonferroni test. Multiple logistic regression analysis was employed to pinpoint independent factors linked to asthenopia.

Results

Out of the 5,009 ophthalmologists who completed the survey, a 40.7% prevalence of asthenopia was identified. Multivariate analysis revealed that good sleep quality (OR: 0.24, 95%CI: 0.20-0.30), moderate sleep quality (OR: 0.47, 95%CI: 0.38-0.59), engaging in daily near vision activities for less than 7 h (OR: 0.76, 95%CI: 0.68-0.86), having daily sleep duration exceeding 7 h (OR: 0.87, 95%CI: 0.77-0.98), and working in tertiary hospitals (OR: 0.88, 95%CI: 0.78-0.99) were protective factors against asthenopia. Conversely, presbyopia was identified as a risk factor (OR: 1.33, 95%CI: 1.04-1.70). All calculated p values were below 0.05. Age, gender, physician level, and eye surgery history were not related factors.

Conclusion

Asthenopia is prevalent among Chinese ophthalmologists, with employment in tertiary hospitals providing a protective effect and presbyopia is a risk factor. Preventive strategies include improving sleep quality, restricting daily near vision activity to under 7 h, and extending daily sleep duration to over 7 h. Further investigation is needed to explore the protective implications of working in tertiary hospitals.

Computer vision syndrome and associated factors in university students and teachers in Nampula, Mozambique

BACKGROUND

Computer Vision Syndrome (CVS) is a complex of eye and visual problems that arise while using a computer or other Video Display Terminal (DVT). With the advent of the COVID-19 pandemic, the use of these DVTs has become indispensable in the lives of students and teachers. This study aims to identify the prevalence of CVS and associated factors in students and teachers at Lúrio University, in Nampula, during the pandemic period.

METHODS

This is a cross-sectional study, carried out between November 2020 and March 2021. The validated CVS questionnaire (CVS-Q) and another semi-structured questionnaire on ergonomic risk factors were applied. Odds ratios (OR) and adjusted odds ratios (aOR) were calculated to measure the association between CVS and computer use conditions.

RESULTS

The prevalence of CVS was 76.6%, and the female gender, age ≤ 20 years, levels I, II, III of course, lack of knowledge about ergonomics, use the computer to study, use more than 6 hours daily, absence of anti-reflex treatment, use of other devices and sitting in an inappropriate chair were risk factors for the occurrence of CVS, while being a teacher was a protective factor.

CONCLUSION

The prevalence of CVS found in this study was high, due to several factors, especially not using ergonomic principles when using computers and other DVTs. There is a need to adopt intervention strategies focused on the most vulnerable groups such as women, age group ≤20 years and students, especially at the first year level, right after entering the University.

Computer vision syndrome among students during remote learning periods: harnessing digital solutions for clear vision

Aim

This study aimed to assess the prevalence of Computer Vision Syndrome (CVS) among children and adolescents in Qatar during the period of remote learning and explore the associated factors and discuss some digital health remedies that might reduce the risk.

Methods

We conducted an analytical cross-sectional study between June and August 2022 by collecting data via telephone interviews with parents of selected students utilizing the Computer Vision Syndrome Questionnaire (CVS-Q).

Results

We completed 1,546 interviews. The mean age of the students was (11 ± 2), male: female ratio was almost 1:1. About one quarter (368, 23.8%) of parents reported a previous diagnosis of visual disturbances among their children with over 88% of them wearing eyeglasses or medical contact lenses. The prevalence of CVS in our sample was about 8% (95%CI: 6.8-9.6). Mother's employment, having positive history of visual disturbances, and excess screen time were found to be significant predictors of CVS.

Conclusion

Health care providers in collaboration with teachers should provide parents with evidence-based strategies to prevent or minimize the digital eye strain among students. In the landscape of remote learning, the implementation of digital remedies emerges as a proactive approach to mitigate the risk of digital eye strain.

Computer Vision Syndrome: An Ophthalmic Pathology of the Modern Era

Digital device usage has increased significantly in last decade among all age groups, both for educational and recreational purposes. Computer vision syndrome (CVS), also known as digital eye strain (DES), represents a range of ocular, musculoskeletal, and behavioral conditions caused by prolonged use of devices with digital screens. This paper reviews the principal environmental, ocular, and musculoskeletal causes for this condition. Due to the high prevalence of DES and frequent usage of digital devices, it is important that eye care practitioners be able to provide advice and management options based on quality research evidence.

[CVS-Q teen©: computer vision syndrome in adolescents and its relationship with digital textbooks]

OBJECTIVE

To analyse the prevalence and progression of computer vision syndrome in secondary and high school students with the CVS-Q© adapted and validated for adolescents, depending on whether they use textbooks or digital books.

METHOD

The CVS-Q© will be adapted by a pilot study in adolescents and a nominal group of visual health specialists, teachers and parents. The resulting version (CVS-Q teen©) will be tested to confirm its quality and applicability and a validation study will be done with visual tests, retest and psychometric analysis. Subsequently, a prospective longitudinal study with four repeated measures will be carried out in adolescents from two secondary schools of San Juan de Alicante (one has replaced textbooks by tablets). Computer vision syndrome will be measured by the CVS-Q teen© with three follow-ups. The prevalence of computer vision syndrome will be analysed according to sociodemographic, visual and digital device use variables. Logistic regression models will be performed, with random effect by student and time of use.

Refractive and Binocular Vision Status and Associated Asthenopia among Clinical Microscopists

Background Clinical microscopists are at a greater risk of developing binocular vision anomalies and asthenopia. Objective To assess the refractive and binocular vision status and to explore the association between the presence of asthenopic symptoms and microscopy work among clinical microscopists working at medical laboratory department. Method This cross-sectional study involved 37 clinical microscopists working at medical laboratory department of Dhulikhel Hospital, Nepal. The study was conducted from January to December 2013. Only those participants who had been using microscope for at least a year were enrolled in this study. Each participant underwent distance visual acuity (VA) assessment, refractions, and orthoptic evaluation, including measurement of distance and near phoria, near point of convergence (NPC), near point of accommodation (NPA), positive fusional vergence (PFV), adduction, and calculation of accommodation convergence/accommodation (AC/A) ratio. The tear test was also carried out in each subject. Information about use of glasses, microscopy work (duration, and time spent per day in microscope), and visual symptoms associated with the use of microscope such as eye strain, headache, double vision, and near vision were collected. Result The mean age of the clinical microscopists was 29 ± 5.7 years. The prevalence of refractive error was 56.76% and the mean spherical equivalent (SE) refractive error was -0.77 ± 0.86 D. Refractive error had neither correlation with microscopy work and asthenopic symptoms associated with it, and nor with binocular vision parametersNPC, AA and AC/A ratio. However, there was a positive association between asthenopic symptoms and microscopy work. There was statistically significant difference between symptomatic and asymptomatic subjects for binocular vision parameters, including NPC, AA and positive fusional vergence (PFV) for near. Conclusion Microscopy work has an impact on near binocular vision. Asthenopic symptoms bear a positive association with microscopy work. Refractive error has no significant correlation with either microscopy works or associated asthenopic symptoms.

Curved Versus Flat Monitors: Interactive Effects of Display Curvature Radius and Display Size on Visual Search Performance and Visual Fatigue

OBJECTIVE

The aim of this study is to examine the interactive effects of display curvature radius and display size on visual search accuracy, visual search speed, and visual fatigue.

BACKGROUND

Although the advantages of curved displays have been reported, little is known about the interactive effects of display curvature radius and size.

METHOD

Twenty-seven individuals performed visual search tasks at a viewing distance of 50 cm using eight configurations involving four display curvature radii (400R, 600R, 1200R, and flat) and two display sizes (33″ and 50″). To simulate curved screens, five flat display panels were horizontally arranged with their centers concentrically repositioned following each display curvature radius.

RESULTS

For accuracy, speed, and fatigue, 33″-600R and 50″-600R provided the best or comparable-to-best results, whereas 50″-flat provided the worst results. For accuracy and fatigue, 33″-flat was the second worst. The changes in the horizontal field of view and viewing angle due to display curvature as well as the association between effective display curvature radii and empirical horopter (loci of perceived equidistance) can explain these results.

CONCLUSION

The interactive effects of display curvature radius and size were evident for visual search performance and fatigue. Beneficial effects of curved displays were maintained across 33″ and 50″, whereas increasing flat display size from 33″ to 50″ was detrimental.

APPLICATION

For visual search tasks at a viewing distance of 50 cm, 33″-600R and 50″ 600R displays are recommended, as opposed to 33″ and 50″ flat displays. Wide flat displays must be carefully considered for visual display terminal tasks.

Digital eye strain: prevalence and associated factors among information technology professionals, Egypt

Digital eye strain (DES) is a growing occupational and public health problem and one of the most frequent reasons for seeking medical care. The objectives of this study are to identify the prevalence and to study some associated personal, ergonomic, and environmental factors of DES among information technology (IT) professionals at Tanta University, Egypt. An interview questionnaire was used to collect data related to socio-demographic, job, ergonomic and environmental characteristics. Computer vision syndrome questionnaire (CVS-Q) was used for the assessment of DES. It was used to measure ocular and visual symptoms related to computer use. CVS-Q includes 16 symptoms that are scored using two rating scales, one for frequency and the other for intensity. A total of 108 IT professionals were included. Prevalence of DES was 82.41%. The most common symptoms were headache (81.5%), burning of the eye (75.9%), and blurred vision (70.4%). Significant predictors of DES were female gender (OR = 2.845), age ≥ 35 years (OR = 1.112), daily computer use more than 6 h (OR = 1.351), duration of work more than 10 years (OR = 1.793), wearing corrective glasses (OR = 5.009), distance from the monitor less than 20 in. (OR = 4.389), not using antiglare screen (OR = 0.214), no brightness adjustment of screen (OR = 0.015), not taking break time during computer work (OR = 0.007), exposure to air pollution (OR = 5.667), use of the air conditioner (OR = 23.021), and exposure to windy environments (OR = 3.588). Prevalence of DES was found to be high among IT professionals. Significant predictors of DES were female gender, older age, wearing eyeglasses, long duration of computer use, unadjusted ergonomic workstation, and dry environment. DES is a problem that can be prevented by increasing knowledge and awareness about DES by providing computer users with eye health education, periodic training on a proper ergonomic computer workstation, and adjustment of the suitable comfortable workplace environment.

Computer vision symptoms in people with and without neck pain

BACKGROUND

Sixty-four to 90% of computer users experience symptoms of computer vision syndrome (CVS). People with CVS symptoms experience neck pain (NP), and people with NP can have visual symptoms.

OBJECTIVES

(1) To examine differences in CVS symptoms in computer users with and without persistent NP. (2) To determine relationships between visual ergonomics, demographics, and CVS in those with and without persistent NP DESIGN: Comparative cross-sectional observational study METHOD: An online survey consisting of multiple questionnaires including the Computer Vision Syndrome Questionnaire (CVS-Q), Visual Symptoms Survey (VSS), and Convergence Insufficiency Symptoms Survey (CISS) was completed by 167 participants.

RESULTS

The persistent NP group had significantly higher CVS-Q, VSS, and CISS scores (p <0.01) compared to controls. No relationships were found between visual ergonomics, demographics, and visual symptoms in both groups.

CONCLUSIONS

People with persitent NP are more likely to present with CVS than controls. Clinicians should consider assessing visual symptoms in people presenting with persisting NP.

Accommodative asthenopia among Romanian computer-using medical students-A neglected occupational disease

Computers have become to play an important role in people's lives throughout the world thus increasing the number of patients with ocular complaints. Also known as computer vision syndrome, accommodative asthenopia might be considered as a neglected occupational condition, but there is no consensus regarding diagnostic criteria, which leads to under-recognition and under-reporting. The aim of the study was to investigate the prevalence, early symptoms and specific preventive measures of accommodative asthenopia among computer-using medical students (n = 420), in a cross-sectional study. The most common early symptoms were: tired eyes/eye strain (86.1%), burning eyes (46.8%), migraines/headaches (46.8%), red-swollen eyes (43%), photophobia (41.8%), temporary blurred vision (35.4%), and eyelid spasms (32.9%). Our study identifies the most frequent early symptoms of accommodative asthenopia as a possible occupational disease, which might serve as a fundament for a future consensus strategy.

Digital Asthenopia: Portuguese Group of Ergophthalmology Survey

INTRODUCTION

Given the increasing use of electronic devices, and the increasing number of complaints with its use, we intend to evaluate the prevalence of manifestations of dry eye and ocular fatigue in a population of individuals, who use the computer daily to perform all their professional tasks, as well as to correlate these complaints with the number of hours of digital use as well as their possible improvement with behavioural measures and use of tear drops.

MATERIAL AND METHODS

A total of 77 individuals (154 eyes) were evaluated on two separate days with a 1-month interval. They completed two questionnaires: OSDI and PEG Eye Fatigue. An objective ocular surface assessment was performed: Schirmer test without anesthetic, DR-1a Dry Eye Monitor™, hyperemia evaluation, lacrimal break up, presence of keratitis and lesions in the conjunctiva, as well as near accommodation point and near convergence point. After the first evaluation, the subjects were divided into two groups: group A (< 2 hours of computer working) and group B (> 2 hours of computer working). Some environmental measures to reduce complaints and recommendation of use of artificial tears were explained to the latter.

RESULTS

There was a statistically significant difference in the majority of the parameters evaluated in the group B, in relation to the morning period (group A) - tear film (p = 0.032), hyperemia (p < 0.001), BUT (p < 0.001), keratitis (p < 0.001), conjunctival lesion (p = 0.002) and accommodation point (p < 0.001). In the evaluation - one month later - there were no statistically significant differences in any of the parameters analysed in the group A, and in group B there was a decrease in most parameters at the end of that period - Schirmer test (p = 0.005), lacrimal film (p = 0.022), keratitis (p < 0.001), conjunctival lesion (p = 0.005) and fatigue score (p < 0.001).

DISCUSSION

It was thus possible to show the appearance of ocular fatigue and ocular surface changes with prolonged use of computers (> 2 hours) as well as a significant improvement in symptomatology (subjective assessment) as well as of ocular surface changes (objective evaluation) with the implementation of postural measures, regular breaks and use of lubricants. This is the first study, to the best of our knowledge, of digital asthenopia in which, in addition to the subjective evaluation, the presence of ocular surface modifications (objective assessment) were evaluated and the respective improvement with the aforementioned ergophthalmological measures were evaluated.

CONCLUSION

This survey highlights the increased overall level of awareness that we need to have to face the rapid and wide-scale changes driven by the emergence of digital technology and, more particularly, its impact on user's vision and posture. We concluded that the longer we use the electronic devices (more than two hours) the more severe the complaints and rates of ocular surface changes are. Environmental and ocular strategies can attenuate or even eliminate the discomfort caused by this syndrome, and increase professional performance and quality of life.

Computer Vision Syndrome and Associated Factors among Computer Users in Debre Tabor Town, Northwest Ethiopia

Background

Globally, computer is one of the common office tools used in various institutions. Using computer for prolonged time led to the users at greater health risk of computer vision syndrome (CVS). Computer vision syndrome is the leading occupational health problem of the twenty-first century. About 70 percent of computer users are suffered from CVS. Besides the health problems, CVS causes inefficiency at workplace and deteriorate quality of work. The problem of CVS and its risk factors are not well known in Ethiopia.

Method

A cross-sectional study was conducted to assess the prevalence of CVS and associated factors among computer user government employees in Debre Tabor town from February to March, 2016. Multistage random sampling method was applied to select 607 study participants, and the data were collected by using a structured questionnaire. Computer vision syndrome was measured by self-reported method. Bivariate and multivariable binary logistic regression analyses were performed using SPSS version 20. Significance level was obtained at 95% CI and p value < 0.05.

Results

The prevalence of CVS was 422 (69.5%) with 95% CI of 65.60, 73.0%. Blurred vision, eyestrain, and eye irritation were the commonest reported symptoms of CVS with proportion of 62.60%, 47.63%, and 47.40%, respectively. Occupation: officer (adjusted odds ratio (AOR) = 4.74) and secretary (AOR = 9.17), daily computer usage (AOR: 2.29), and preexisting eye disease (AOR = 3.19) were risk factors for CVS. However, computer users with high payment, who took regular health break, and with good knowledge on computer safety measures were less impacted by CVS.

Conclusion

The prevalence of computer vision syndrome was found to be higher in Debre Tabor town. Monthly income, occupation, daily computer usage, regular health break, knowledge, and preexisting eye disease were predictor variables for CVS. Optimizing exposure time, improving awareness on safety measures, and management support are important to tackle CVS.

Computer vision syndrome and ergonomic practices among undergraduate university students

AIM

To determine the prevalence of computer vision syndrome (CVS) and ergonomic practices among students in the Faculty of Medical Sciences at The University of the West Indies (UWI), Jamaica.

METHOD

A cross-sectional study was done with a self-administered questionnaire.

RESULTS

Four hundred and nine students participated; 78% were females. The mean age was 21.6 years. Neck pain (75.1%), eye strain (67%), shoulder pain (65.5%) and eye burn (61.9%) were the most common CVS symptoms. Dry eyes (26.2%), double vision (28.9%) and blurred vision (51.6%) were the least commonly experienced symptoms. Eye burning (P = .001), eye strain (P = .041) and neck pain (P = .023) were significantly related to level of viewing. Moderate eye burning (55.1%) and double vision (56%) occurred in those who used handheld devices (P = .001 and .007, respectively). Moderate blurred vision was reported in 52% who looked down at the device compared with 14.8% who held it at an angle. Severe eye strain occurred in 63% of those who looked down at a device compared with 21% who kept the device at eye level. Shoulder pain was not related to pattern of use.

CONCLUSION

Ocular symptoms and neck pain were less likely if the device was held just below eye level. There is a high prevalence of Symptoms of CVS amongst university students which could be reduced, in particular neck pain and eye strain and burning, with improved ergonomic practices.

A survey of the prevalence of fatigue, its precursors and individual coping mechanisms among U.S. manufacturing workers

Advanced manufacturing has resulted in significant changes on the shop-floor, influencing work demands and the working environment. The corresponding safety-related effects, including fatigue, have not been captured on an industry-wide scale. This paper presents results of a survey of U.S. manufacturing workers for the: prevalence of fatigue, its root causes and significant factors, and adopted individual fatigue coping methods. The responses from 451 manufacturing employees were analyzed using descriptive data analysis, bivariate analysis and Market Basket Analysis. 57.9% of respondents indicated that they were somewhat fatigued during the past week. They reported the ankles/feet, lower back and eyes were frequently affected body parts and a lack of sleep, work stress and shift schedule were top selected root causes for fatigue. In order to respond to fatigue when it is present, respondents reported coping by drinking caffeinated drinks, stretching/doing exercises and talking with coworkers. Frequent combinations of fatigue causes and individual coping methods were identified. These results may inform the design of fatigue monitoring and mitigation strategies and future research related to fatigue development.

The relationship between occupational noise and vibration exposure and headache/eyestrain, based on the fourth Korean Working Condition Survey (KWCS)

INTRODUCTION

The individual and combined effect of occupational noise and vibration exposures, on workers' health has not been thoroughly investigated. In order to find better ways to prevent and manage workers' headache, this study aimed to investigate the effects of occupational noise and vibration exposure on headache/eyestrain.

METHODS

We used data from the fourth Korean Working Condition Survey (2014). After applying inclusion and exclusion criteria, 25,751 workers were included. Occupational noise and vibration exposure and the prevalence of headache/eyestrain were investigated by self-reported survey. Chi-square tests were used to compare differences in baseline characteristics between the group with headache/eyestrain and the group without. Odds ratios and 95% confidence intervals were estimated using a logistic regression model adjusted for several covariates. Area under the receiver operating characteristics curve (AUROC) analysis was used to evaluate the effect of occupational noise and/or vibration exposure.

RESULTS

Among the 25,751 study subjects, 4,903 had experienced headache/eyestrain in the preceding year. There were significant differences in age, education level, household income, occupational classification, shift work, occupational vibration exposure, and occupational noise exposure between the two groups (all p<0.05). The odds ratios between each exposure and headache/eyestrain increased proportionally with the level of exposure, increasing from 1.08 to 1.26 with increasing vibration exposure, and from 1.25 to 1.41 with increasing noise exposure. According to the AUROC analysis, the predictive power of each exposure was significant, and increased when the two exposures were considered in combination.

DISCUSSION

The findings of this study show that both occupational noise and vibration exposures are associated with headache/eyestrain; noise exposure more strongly so. However, when the two exposures are considered in combination, the explanatory power for headache/eyestrain is increased. Therefore, efforts aimed at reducing and managing occupational noise and vibration exposure are crucial to maintaining workers' health.

A reliable and valid questionnaire was developed to measure computer vision syndrome at the workplace

OBJECTIVES

To design and validate a questionnaire to measure visual symptoms related to exposure to computers in the workplace.

STUDY DESIGN AND SETTING

Our computer vision syndrome questionnaire (CVS-Q) was based on a literature review and validated through discussion with experts and performance of a pretest, pilot test, and retest. Content validity was evaluated by occupational health, optometry, and ophthalmology experts. Rasch analysis was used in the psychometric evaluation of the questionnaire. Criterion validity was determined by calculating the sensitivity and specificity, receiver operator characteristic curve, and cutoff point. Test-retest repeatability was tested using the intraclass correlation coefficient (ICC) and concordance by Cohen's kappa (κ).

RESULTS

The CVS-Q was developed with wide consensus among experts and was well accepted by the target group. It assesses the frequency and intensity of 16 symptoms using a single rating scale (symptom severity) that fits the Rasch rating scale model well. The questionnaire has sensitivity and specificity over 70% and achieved good test-retest repeatability both for the scores obtained [ICC = 0.802; 95% confidence interval (CI): 0.673, 0.884] and CVS classification (κ = 0.612; 95% CI: 0.384, 0.839).

CONCLUSION

The CVS-Q has acceptable psychometric properties, making it a valid and reliable tool to control the visual health of computer workers, and can potentially be used in clinical trials and outcome research.

Computer vision syndrome: a study of knowledge and practices in university students

INTRODUCTION

Computer vision syndrome (CVS) is a condition in which a person experiences one or more of eye symptoms as a result of prolonged working on a computer.

OBJECTIVES

To determine the prevalence of CVS symptoms, knowledge and practices of computer use in students studying in different universities in Malaysia, and to evaluate the association of various factors in computer use with the occurrence of symptoms.

MATERIAL AND METHODS

In a cross sectional, questionnaire survey study, data was collected in college students regarding the demography, use of spectacles, duration of daily continuous use of computer, symptoms of CVS, preventive measures taken to reduce the symptoms, use of radiation filter on the computer screen, and lighting in the room.

RESULTS

A total of 795 students, aged between 18 and 25 years, from five universities in Malaysia were surveyed. The prevalence of symptoms of CVS (one or more) was found to be 89.9%; the most disturbing symptom was headache (19.7%) followed by eye strain (16.4%). Students who used computer for more than 2 hours per day experienced significantly more symptoms of CVS (p=0.0001). Looking at far objects in-between the work was significantly (p=0.0008) associated with less frequency of CVS symptoms. The use of radiation filter on the screen (p=0.6777) did not help in reducing the CVS symptoms.

CONCLUSION

Ninety percent of university students in Malaysia experienced symptoms related to CVS, which was seen more often in those who used computer for more than 2 hours continuously per day.

A survey of visually induced symptoms and associated factors in spectators of three dimensional stereoscopic movies

BACKGROUND

The increasing popularity of commercial movies showing three dimensional (3D) computer generated images has raised concern about image safety and possible side effects on population health.This study aims to (1) quantify the occurrence of visually induced symptoms suffered by the spectators during and after viewing a commercial 3D movie and (2) to assess individual and environmental factors associated to those symptoms.

METHODS

A cross-sectional survey was carried out using a paper based, self administered questionnaire. The questionnaire includes individual and movie characteristics and selected visually induced symptoms (tired eyes, double vision, headache, dizziness, nausea and palpitations). Symptoms were queried at 3 different times: during, right after and after 2 hours from the movie.

RESULTS

We collected 953 questionnaires. In our sample, 539 (60.4%) individuals reported 1 or more symptoms during the movie, 392 (43.2%) right after and 139 (15.3%) at 2 hours from the movie. The most frequently reported symptoms were tired eyes (during the movie by 34.8%, right after by 24.0%, after 2 hours by 5.7% of individuals) and headache (during the movie by 13.7%, right after by 16.8%, after 2 hours by 8.3% of individuals). Individual history for frequent headache was associated with tired eyes (OR = 1.34, 95%CI = 1.01-1.79), double vision (OR = 1.96; 95%CI = 1.13-3.41), headache (OR = 2.09; 95%CI = 1.41-3.10) during the movie and of headache after the movie (OR = 1.64; 95%CI = 1.16-2.32). Individual susceptibility to car sickness, dizziness, anxiety level, movie show time, animation 3D movie were also associated to several other symptoms.

CONCLUSIONS

The high occurrence of visually induced symptoms resulting from this survey suggests the need of raising public awareness on possible discomfort that susceptible individuals may suffer during and after the vision of 3D movies.

[Epidemiology and related factor analysis of visual fatigue in university students of Haidian District of Beijing]

OBJECTIVE

To analyze and explore the epidemiological characteristicss and related factors for visual fatigue among university students in Haidian District of Beijing.

METHODS

The investigation with questionnaires was conducted in 2 246 undergraduates and postgraduates from four universities in Haidian District by multi-level stratified cluster sampling. Factor analysis and multivariate Logistic regression model were conducted to explore the related factors for visual fatigue.

RESULTS

Among the university students, the total prevalence rate of visual fatigue was 64.9%, and the prevalence rates of males, females, undergraduates and postgraduates were 65.1%, 64.7%, 58.9% and 75.7%, respectively. The result of multivariate logistic regression analysis showed that bad living environment conditions, improper computer use and bad health status were significantly associated with increased risk of visual fatigue, the ORs (95% CI) were 1.185 (1.078, 1.302), 1.490 (1.355, 1.640) and 1.323 (1.182, 1.481), respectively; good sleep and mental status, good psycho-social state, and good factors of habits and diets might be protective against visual fatigue, the ORs (95% CI) were 0.691 (0.628, 0.760), 0.793 (0.720, 0.873) and 0.649 (0.587, 0.717), respectively.

CONCLUSION

The university students showed higher prevalence rate of visual fatigue. Psychological state, environment, health status, diets and habits were related to the development of visual fatigue. Health education should be strengthened among university students to prevent the adverse effects of visual fatigue on their health.

[Eye symptoms in office employees working at computer stations]

BACKGROUND

The aim of the study was to measure the prevalence and intensity of eye symptoms in office workers who use computers on a regular basis, and to find out if the symptoms depend on the duration of computer use and other work-related factors.

MATERIAL AND METHODS

Office workers employed at large social services companies in two cities (Warszawa and Katowice) were invited to fill in a questionnaire (cross-sectional study). The questions included work history and history of last-week eye symptoms and eye-related complains. Altogether 477 men and women returned the completed questionnaires. Between-group symptom differences were tested by the chi-square test and verified by the results of multivariate logistic analysis. The examined effects included the role of daily computer use and lighting conditions at work stations.

RESULTS

The examined persons complained of such eye symptoms as eye strain, visual acuity impairment and mucosal dryness or eye burning. The following values of symptom prevalence were found in women and men, respectively: eye strain 50.7% and 32.6%, disturbed visual acuity 38.3% and 21.2%, mucosal dryness and eye burning 46.5% and 24.2%. The results of multivariate analysis confirmed the statistically significant effects of lighting intensity and screen flickering on the occurrence of symptoms.

CONCLUSIONS

Frequent occurrence of eye symptoms and their associatation with some characteristics of the work environment point to the need of observing ergonomic standards of work stations and of the usage of computers at work.

[Effect of visual work on the tear film and degree of the eye strain]

BACKGROUND

The aim of this study was to assess the impact of the visual work on the tear film and the degree of eye strain.

MATERIALS AND METHODS

The survey was conducted among 50 people working 4 h with different types of monitors (CRT, LCD) and without a monitor. Schirmer's test and evaluation of the degree of eye strain were performed in all subjects before and after work.

RESULTS

The studies revealed no significant change in Schirmer's test. Most people reported eye fatigue after every kind of visual work. The highest degree of eye strain was noted after work with the CRT display screen, especially among people with dry eye syndrome.

CONCLUSION

The studies revealed no significant impact of various visual works on the tear film. However, they showed that any kind of intense eye work may cause eye irritation and strain, particularly in the people affected by dry eye syndrome.

Perceived job stress and health complaints at a bank call center: comparison between inbound and outbound services

This study investigated how perceived job stress and health status differ, as well as the relationships to inbound (incoming calls) versus outbound (outgoing calls) calling activities, for call center workers in a bank in Taiwan. The sample bank employed 289 call center workers at the time of the survey, ranging in age from 19 to 54 yr old. Data were obtained on individual factors, health complaints, perceived level job stress, and major job stressors. Overall, 33.5% of outbound operators and 27.1% of inbound operators reported frequently or always experiencing high stress at work, however, the differences between inbound and outbound operators were insignificant. "Having to deal with difficult customers" was the most frequent job stressor for all workers. Musculoskeletal discomfort, eye strain, and hoarse or sore throat were the most prevalent complaints among call center workers. The relationship between perceived job stress and health complaints indicated that workers who perceived higher job stress had significantly increased risk of multiple health problems, including eye strain, tinnitus, hoarse or sore throat, chronic cough with phlegm, chest tightness, irritable stomach or peptic ulcers, and musculoskeletal discomfort (with odds ratios ranging from 2.13 to 8.24). These analytical results suggest that perceived job stress in the call center profoundly affected worker health. This study identified main types of job stressors requiring further investigation.

Computer vision syndrome: a study of the knowledge, attitudes and practices in Indian ophthalmologists

PURPOSE

To study the knowledge, attitude and practices (KAP) towards computer vision syndrome prevalent in Indian ophthalmologists and to assess whether 'computer use by practitioners' had any bearing on the knowledge and practices in computer vision syndrome (CVS).

MATERIALS AND METHODS

A random KAP survey was carried out on 300 Indian ophthalmologists using a 34-point spot-questionnaire in January 2005.

RESULTS

All the doctors who responded were aware of CVS. The chief presenting symptoms were eyestrain (97.8%), headache (82.1%), tiredness and burning sensation (79.1%), watering (66.4%) and redness (61.2%). Ophthalmologists using computers reported that focusing from distance to near and vice versa (P =0.006, chi2 test), blurred vision at a distance (P =0.016, chi2 test) and blepharospasm (P =0.026, chi2 test) formed part of the syndrome. The main mode of treatment used was tear substitutes. Half of ophthalmologists (50.7%) were not prescribing any spectacles. They did not have any preference for any special type of glasses (68.7%) or spectral filters. Computer-users were more likely to prescribe sedatives/anxiolytics (P = 0.04, chi2 test), spectacles (P = 0.02, chi2 test) and conscious frequent blinking (P = 0.003, chi2 test) than the non-computer-users.

CONCLUSIONS

All respondents were aware of CVS. Confusion regarding treatment guidelines was observed in both groups. Computer-using ophthalmologists were more informed of symptoms and diagnostic signs but were misinformed about treatment modalities.

[Asthenopia in VDT users: our experience]

The aim of this study was to investigate the relationship between asthenopia and work with video display terminals (VDT). 62 office workers (29 males and 33 females), that use VDT for more than 20 hours each week, were investigated by means of standardized questionnaires (elaborated by the Italian Society of Occupational Medicine and Industrial Hygiene). The authors analyzed the prevalence of occupational asthenopia and its correlation with the duration of weekly VDT use and the presence of refractive alterations. It was demonstrated a prevalence of asthenopia of 51% and a statistically significant correlation between the entity of asthenopic symptoms and number of weekly hours and years of work at VDT, in particular in subjects with presbyopia.

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.

[Asthenopia and work at video display terminals: study of 191 workers exposed to the risk by administration of a standardized questionnaire and ophthalmologic evaluation]

VDT (Visual Display Terminals) are commonly used in a wide range of occupational fields. Over the last ten years a number of studies have shown that ocular symptoms are the form of discomfort most frequently experienced by subjects who work at VDT. The symptoms as a whole characterize a complex syndrome named "asthenopia" and have been seen as a consequence of prolonged, fixed and closely oriented vision. In our study we have evaluated data derived from a standardized questionnaire (a series of questions elaborated and promoted by the Italian Society of Occupational Medicine and Industrial Hygiene). It was administered to a group of 191 workers who utilise VDT for more than 20 hours each week. We also took into consideration the results of ophthalmologic medical examinations performed on this particular group of workers. Prevalence of occupational asthenopia we found to be lower in this group than in the case of other reported investigations, though it proved to be higher in the case of female subjects. According to the Literature, symptoms intensity is related to the duration of weekly VDT use, there being no significant association with the number of years spent working at VDT. Our results show that prevalence of asthenopia was not significantly influenced by refractive alterations and this unexpected outcome might be explained by taking into account the small-size group of subjects affected by hypermetropic defects. It is well known that these are the most important factors in conditioning asthenopia. Our finding indicates the need for further research, which should include a larger group of VDT workers with refractive alterations and furthermore take into consideration environmental variables such as climate and illumination, since these are co-aetiological factors, known or suspected, of occupational asthenopia.

Musculoskeletal disorders and visual strain in intensive data processing workers

BACKGROUND

This study was conducted for a UK Trade Union in response to increasing numbers of health complaints among intensive computer workers in a data processing environment.

AIM

To estimate prevalence of musculoskeletal pain/discomfort and visual strain symptoms among data processing workers and to explore associations with work factors.

METHODS

A self-report questionnaire was distributed to data processors (n = 175) and a control group (n = 129) in the same organization.

RESULTS

Eighty-six per cent of data processors reported musculoskeletal pain/discomfort in the previous year, with the highest prevalence rate found for the neck (58%). The 12 month reported prevalence for visual strain symptoms was 47%, tired eyes (41%) was the most commonly reported symptom. In the last week, 56% reported pain/discomfort and 25% visual strain symptoms. Data processors reporting pain in the previous year were more likely to be dissatisfied with their jobs (P < 0.01), to report a lack of choice in deciding what they did at work (P < 0.02), to have insufficient time to complete work (P < 0.05) or to receive help from others when time was limited (P < 0.03).

CONCLUSION

The prevalence of self-reported musculoskeletal pain/discomfort and visual strain symptoms was high among data processors. A systematic approach to risk reduction addressing organizational, psychosocial and physical work factors is required. This study has implications for reorganization of this and other intensive computer work, given the increasing requirement for intensive computing work in many industrial sectors. More research is needed to investigate interactions between job demands and support systems for these workers.

Prevalence of Eye Strain Among Radiologists: Influence of Viewing Variables on Symptoms

OBJECTIVE

To determine the prevalence of and factors contributing to eye strain among radiologists, we examined the influence of the viewing method (PACS vs hard-copy film), age, case volume, technique, work habits, and workstation design on symptoms.

MATERIALS AND METHODS

An Internet-based survey was sent to 2,700 radiologists randomly selected from the membership database of the Radiological Society of North America. Questions included demographic information, viewing method, work habits, and workstation design. Common eye strain symptoms were evaluated on a 5-point Likert scale. Chi-square analysis, analysis of variance, and step-wise and regression analyses were performed to evaluate codependence of the explanatory variables with eye strain.

RESULTS

The adjusted response rate was 14% (380 respondents). The largest age cohort was 36-50 years. The prevalence of eye strain was 36% and was not affected by the viewing method (PACS vs film). Increased symptoms could be independently predicted in radiologists who were women (p <0.001), had longer work days (p=0.009), took fewer breaks (p=0.03), reported screen flicker (p=0.0003), and performed CT screening (p=0.04). Working hours had the strongest influence on eye strain. Eye strain was increased in those who reported studies for longer than 6 hr per day (p=0.01) and decreased in those who took breaks every hour (p=0.04). Symptoms were independent of the length of the break taken and of other workstation and technique factors.

CONCLUSION

Eye strain was common among the radiologists in our study population, with no significant difference between PACS and hard-copy film users. Taking frequent short breaks, eliminating screen flicker, and limiting the number of CT screening studies interpreted may improve symptoms.

[Survey on visual and musculoskeletal symptoms in VDT workers]

With the spread of visual display terminals (VDT) in offices, the numbers of workers using VDT and the working hours at such equipment have increased rapidly in recent years. Also, preventive measures for fatigue have been proposed and the office-working environment has been improved. To examine the effects of the rapid changes in working conditions and environment on the health of VDT workers, we conducted a questionnaire survey in 2002. A self-reported questionnaire was distributed to 3,927 office workers; 2,374 (60.5%) responded. Subjects whose questionnaires had missing data were excluded from analysis. As a result, 1,406 (male: 1,069, female: 337) workers aged 20 to 59 were subjected to analysis. By a logistic regression model, we examined the association between VDT use and visual and musculoskeletal symptoms. Prevalence of eye strain and/or pain (72.1%) was the highest, followed by neck stiffness and/or pain (59.3%), low back stiffness and/or pain (30.0%) and hand or arm strain and/or pain (13.9%). Women consistently reported more discomfort than men. As a result of the logistic regression model, eye strain and/or pain was associated with dissatisfaction with airflow, but not with factors affecting visual symptoms as reported in previous studies, for example, reflection of light and blurred characters on the screen. It was thought that airflow appeared as a risk factor because the lighting environment had been improved in offices to prevent reflection of light on the screen. Neck stiffness and/or pain was associated with raising the shoulders during VDT work, the unsuitable shape of the computer mouse for a hand, and the inconvenient arrangement of the mouse in relation to the body. Hand or arm strain and/or pain were associated with the arrangement of the mouse and inappropriate height of the desk. Low back stiffness and/or pain were associated with dissatisfaction with the chair and using the keyboard without a wrist rest. Although measures to prevent fatigue had been implemented for VDT workers, risk factors for musculoskeletal symptoms would be the same as in previous studies.

[Relation of asthenopia and some ophthalmological, neuropsychological, and musculoskeletal parameters in workers assigned to video display terminals]

BACKGROUND

Since the use of video display units (VDU) has become widespread in the workplace, more and more research has been conducted to evaluate the possible onset of adverse effects.

OBJECTIVES

We carried out a multidisciplinary investigation on a group of 660 VDU operators working for a service agency, aimed at analysing the relationship between ophthalmological, musculoskeletal and neuropsychological parameters and asthenopia.

METHODS

In this study we propose a method for a qualitative and quantitative evaluation of the asthenopic syndrome based on data collected with an easy semi-structured questionnaire.

RESULTS AND CONCLUSIONS

No relationship between asthenopia and refractive alteration was noted, whereas a significant association was observed between a lengthened convergence near point and the average time of daily VDU exposure. A significant relationship was also shown between asthenopia, cervical and lumbar disorders, and neuropsychological symptoms. The method for evaluation of asthenopia and the results of this study suggest useful implications in health surveillance programs. After an appropriate validation procedure, this method could represent a useful screening tool and a valid support for preventive interventions. The use of this instrument in longitudinal studies will also provide the opportunity of verifying the existence of long-term effects due to VDU exposure.

[Manifestations of asthenopia in Black subjects]

OBJECTIVE

To report the relative frequency of the asthenopic complaints in an african black population.

METHODS

Data from 184 records of African black subjects with asthenopic complaints and a normal ocular examination between January 1996 and December 1998 were considered.

RESULTS

There were 87 males (47.3%) and 97 females (52.7%). The mean age was 24.6 +/- 9.2 years with a sex ratio of 1:1. Asthenopic symptoms were: headache (47.0%), ocular pain (37.0%), tearing (24.5%), blurred vision (23.4%), photophobia (20.1%), burning sensation (12.5%), foreign-body sensation (8.7%), red eyes (4.3%) and diplopia (4.3%). Asthenopic subjects with headache had more associated symptoms. Headache was 2-3 times more frequently associated with the presence of tearing, foreign-body sensation and burning complaints than others.

CONCLUSION

African black people seem to present the same asthenopic symptoms as in other races. Headache is the main symptom. Tearing, foreign-body and burning sensation are the most common complaints associated with asthenopic headache.

[Complex method of "operative" and "long-term" correction of visual dysfunction among aviation specialists]

The article demonstrates analysis of present methods aimed at functional stimulation of vision. The authors show leading role of laser stimulation methods, justify terms--"operative" and "long-term" correction of vision--referring to occupational activities of aviation professionals.

Microbiological pollution and ocular infection in CAD operators: an on-site investigation

A large number of workers are currently employed in tasks involving the use of computer based equipment. Much research has been carried out both on prevalence and incidence of ocular and visual disorders as well as on occupational asthenopia. Less attention has been given to investigating the possibility of a microbiological pollution of Video Display Unit (VDU) workstations and to the consequent possible development of work-related ocular infections. The authors investigated the presence of bacteria and fungi on Computer Assisted Design (CAD) workstations and in the conjunctival sac of the operators.

Effective medical examination of VDT workers using a new testing method of ocular alignment

To investigate the relationship between asthenopia of VDT workers and the ocular alignment, we measured far and near alignment of 407 subjects (74 VDT workers with asthenopia, 137 VDT workers without asthenopia, and 196 non-VDT workers) using Total Vision tester (VT-500). There was no relationship between the asthenopia and the records of far alignment test. On the other hand, the incidence of exophoria and convergence insufficiency type in near alignment test was significantly high in the group of VDT workers with asthenopia. From these results, we speculate that cases who have exophoria or show incomplete fusional response measured under the near testing distance (50 cm) tend to complain of asthenopia.

[Risk factors for asthenopia among computer terminal operators]

OBJECTIVE

To study the incidence of asthenopia among computer terminal operators as compared to unexposed administrative workers and to identify the risk factors associated with this condition.

MATERIAL AND METHODS

A sample of 35 computer terminal operators and 70 unexposed administrative workers from eight computing centers at an educational institution were included in the study. The risk factors studied were: lighting, contrast, type of lighting, screen type, electrostatic field, eye to monitor distance, time and number of hours worked, age, use of corrective lenses, seniority and overtime. Asthenopia was clinically identified as the presence of at least one sign and symptom present in a given workday.

RESULTS

Asthenopia was found in 68.5% of the exposed group and in 47.7% of the unexposed group (p < 0.05). Among the risk factors studied, working for more than four hours at the video display terminal was shown to have a significant association with asthenopia (p < 0.05).

CONCLUSIONS

A recommendation is made to take breaks during the workday at computer terminals in order to avoid visual fatigue. Also, more extensive studies should be carried out in our population to establish safety criteria and to standardize work activities using computer terminals.

Is there a typical VDT patient? A demographic analysis

BACKGROUND

The use of video display terminals (VDT) in the workplace is growing rapidly. Visual problems associated with computer use are increasing apace. Recognizing and addressing these needs are vital tasks for the optometric practitioner. This paper examines the demographics, prevalence of symptoms, and other work- and vision-related factors among VDT workers. Understanding the characteristics of a typical patient can aid in developing effective treatment protocols.

METHODS

Twenty-two optometrists collected data from 324 patients who work on VDT screens for a minimum of 2 hours per day. A questionnaire was used to collect the data. Along with reporting the patients' dry manifest refraction results, the survey instrument also included a self-report of experienced symptoms.

RESULTS

The prototypical patient, based on the total subject population, is a 38-year old, mildly myopic female who uses the computer screen about 5 hours per day. Average total VDT work experience is about 5 years. Most of the patients use full-color screens and sit between 21 and 22 inches away from the screen. A variety of visual symptoms is reported, with eyestrain (65 percent) and headaches (42 percent) being the most common complaints.

CONCLUSIONS

Between 75 percent (results of this study) and 88 percent (reported by NIOSH) of patients who use a VDT regularly are likely to be symptomatic. This study has helped to identify the "typical" VDT user and the symptoms this user is most likely to report. The next step is to develop a diagnostic and treatment protocol by which optometrists can prescribe for and potentially prevent these computer-related vision problems.

The frequency of occurrence and severity of side-effects of immersion virtual reality

Virtual reality (VR) has become increasingly well-known over the last few years. However, little is known about the side-effects of prolonged immersion in VR. This study set out to investigate the frequency of occurrence and severity of side-effects of using an immersion VR system. Out of 146 subjects, 61% reported symptoms of malaise at some point during a 20-min immersion and 10-min post-immersion period. These ranged from symptoms such as dizziness, stomach awareness, headaches, eyestrain and lightheadedness to severe nausea. These symptoms caused 5% of the subjects to withdraw from the experiment before completing their 20-min immersion period. Further research needs to be conducted that attempts to identify those factors that play a causative role in the side-effects of the VR system, and that looks for methods of reducing these side-effects.

[Investigation of subjective symptoms among visual display terminal users and their affecting factors--analysis using log-linear models]

In order to evaluate factors affecting visual and musculoskeletal symptoms by visual display terminal (VDT) operation, a questionnaire survey was conducted among clerical workers in Chiba university. The results were as follows: 1) Of these workers, 81.9% engaged in VDT operation. For most of the subjective symptoms, the prevalence rates tended to increase with the degree of VDT use. 2) These complaints were combined to give visual and musculoskeletal symptom scores. Both of the scores were higher among females than males, and the musculoskeletal symptom score was significantly higher. No difference was found in regard to age. 3) Analysis using log-linear models was performed to evaluate the effects of sex and age. The results showed that the visual and musculoskeletal symptom scores were significantly higher among the workers operating VDTs for one or more hours per day than among those who did not operate them at all. Analysis of the effects of VDT workloads revealed that VDT use for five or more days per week significantly increased the prevalence rates of both symptoms. Their use for less than four days per week affected neither of the symptoms. With regard to operating time per day or length of VDT use, no differences were found. 4) This investigation suggested that the VDT workloads were not so heavy and that the effects on each symptom were minor among the subjects of the present survey. However, it is important that consideration be given to ensure that the workloads for workers who operate VDTs every day not be too heavy.

The effect of sleep deprivation and sustained military operations on near visual performance

A group of military servicemen were deprived of sleep for 65 h while they carried out a simulated military mission with a high visual workload. Their performance in a series of near vision tests was monitored. In general, the visual system was found to be resilient to the stress of sleep loss, the subjects experiencing mild symptoms of asthenopia (eyestrain). However, after 48 h without sleep there was a reduction in amplitude of convergent fusional reserves and a decrease in contrast sensitivity to a spatial frequency of 6 cycles/degree. A disruption in diurnal rhythms for these parameters was suggested. The results are considered in terms of the maintenance of visual efficiency and comfort with loss of sleep, and have implications for both the military and civilians involved in shift work and long work schedules.

Validation of the General Health Questionnaire in female video display unit (VDU) operators in Singapore

Fifty-seven Chinese female Video Display Unit operators employed in a multi-national company were asked to complete the 28-item General Health Questionnaire (GHQ-28). This is part of a study on stress and asthenopia in this group of workers. Validity of the GHQ-28 was determined by comparison with the Clinical Interview Schedule (CIS). The GHQ-28 was found to give optimum results with a cut-off score of 5/6. The CIS classified 28.07% as cases and this was comparable to the estimated prevalence of 28.03% derived from the GHQ.

[Asthenopia and objective ophthalmological findings in a population of 2058 VDT operators in Lombardy]

A large population of 2058 VDT operators from all compartments in Lombardia of a large national company was studied. An "ergophthalmological" questionnaire was administered to all subjects, followed by an ophthalmological-orthoptic examination. Ametropias showed a prevalence of 51.9%; the most common refractive defect was myopia followed by astigmatism and hyperopia. Heterophorias with bad or mediocre compensation had a prevalence of 4.1 and 11% respectively. The study of symptoms showed a frequency of 23.5% of intense asthenopic complaints and 21.1% of less severe and less frequent symptomatology. Asthenopia was significantly correlated (chi square) with sex, VDT exposure, refraction, presbyopia, and decompensated heterophorias.

Visual fatigue in video display terminal operators: objective measure and relation to environmental conditions

The lighting conditions, luminance, contrast, and design of the workplace were studied in video display terminal (VDT) work stations operated by a group of female VDT data-acquisition clerks. VDT-induced symptoms were assessed by means of subject answers to a questionnaire. To measure VDT-induced ocular fatigue objectively, refraction power was determined before and at the end of workshift by an infrared autorefractometer. Job-induced refraction changes were then related to visual complaints and conditions in the workplace. The results confirmed that VDT data-acquisition work can lead to temporary myopia (myopization) in a remarkable percentage of operators; a significant correlation between eye discomfort, ocular asthenopia, and myopization was also found. Illumination levels, luminance, and contrast seem to be of paramount importance regarding visual symptoms: neither asthenopia nor myopization was observed when all of these conditions were adequate. If the ergonomic design of the workplace and the viewing distance are adequate, there are also usually fewer musculoskeletal symptoms. Our results suggest that changes in the ocular refraction status before and at the end of the work-shift, as determined by an automatic refractometer, provide a good objective index of VDT-induced "ocular fatigue", which in our study proved to be significantly related to workplace conditions.

[Factors affecting subjective symptoms of VDT workers]

In 1983, 285 (male: 129, female: 156) VDT workers and 60 (male: 30, female: 30) control subjects were examined in order to detect the factors affecting the subjective symptoms of VDT workers. Biological information (for example: sex, age), life histories, information about VDT work, tests (for example: visual acuity), symptoms and interferences to daily life of VDT workers and control subjects were collected. The following results were obtained. Female VDT workers experienced more fatigue from commuting to work, stiffness in shoulders, distant blurred vision complaints of visual acuity and sum of the scores of ocular complaints than female control subjects. Only among female VDT workers, the longer the daily working hours, the greater were their ocular symptoms. A remarkable relationships were observed between psychological burden factors (for example: self-control of VDT work, sensation of excessive VDT work) and subjective symptoms of the VDT workers (both sexes). In particular, VDT workers who considered VDT work to be excessive had marked by greater subjective symptoms than those who did not.

General binocular dysfunctions in an urban optometry clinic

The prevalence of general binocular dysfunction with asthenopia was determined for non-presbyopes at an urban optometry clinic serving municipal workers and their dependents. Of the sample of 119 patients, 42.9% had jobs with heavy desk work demands (primarily secretarial and clerical) and 39.5% were students. The prevalence of symptomatic general binocular dysfunction was 21.0%. Accommodative dysfunctions were the most commonly encountered condition at 16.8%. Symptomatic near esophoria was found in 5.9% of patients and convergence insufficiency in 4.2%. Both vergence dysfunctions overlapped with accommodative dysfunctions.

Short-term changes in eyestrain of VDU users as a function of age

Operators at a Swedish Telecom Directory Enquiry Centre participated in tests of eyestrain including measures of accommodation and convergence near points, focusing accuracy, and dark focus. The optometric measurements were conducted before and after work at a visual display unit (VDU) and in two control conditions, with or without job rotation. Visual focus of accommodation was measured with a modified version of the field laser optometer method. The results showed no differential eyestrain effects, either in near points of accommodation and convergence or in focusing accuracy, between the three tasks. A small, age-dependent difference in dark focus was apparent after work in the job-rotation phase. It is concluded that the VDU work was not in itself conducive to eyestrain, and that, under the job conditions obtained in the present investigation, changes in the variables studied must be primarily attributed to other factors, such as age and workload on the day of testing.