Effects of job-related stress and burnout on asthenopia among high-tech workers.

Eye- and vision-related symptoms are the most frequent health problems among computer users. The findings of eye strain, tired eyes, eye irritation, burning sensation, redness, blurred vision and double vision, when appearing together, have recently been termed 'computer vision syndrome', or asthenopia. To examine the frequency and intensity of asthenopia among individuals employed in research and development departments of high-tech firms and the effects of job stress and burnout on ocular complaints, this study included 106 subjects, 42 high-tech workers (study group) and 64 bank employees (control group). All participants completed self-report questionnaires covering demographics, asthenopia, satisfaction with work environmental conditions, job-related stress and burnout. There was a significant between-group difference in the intensity of asthenopia, but not in its frequency. Burnout appeared to be a significant contributing factor to the intensity and frequency of asthenopia. This study shows that burnout is a significant factor in asthenopic complaints in high-tech workers. PRACTITIONER SUMMARY: This manuscript analyses the effects of psychological environmental factors, such as job stress and burnout, on ocular complaints at the workplace of computer users. The findings may have an ergonomic impact on how to improve health, safety and comfort of the working environment among computer users, for better perception of the job environment, efficacy and production.

The role of attributional bias and visual stress on the improvement of reading speed using colored filters.

This study tested the predictions derived from two explanatory theoretical models of the effects of colored filters on reading speed: the theory of attributional bias and the theory of visual stress associated with reading. The experimental group consisted of 27 secondary school students (14 boys, 13 girls) diagnosed with the Meares-Irlen syndrome; the control group had 27 students paired in age and sex with the experimental group. The mean age of the sample was 12 years, 10 months (SD = 8.9 mo.). The effects of colored filters on reading speed and accuracy were tested using a word reading test and a visual stress induction text. The presentation method tapped individuals' visual sensitivity and response criteria. The results support some predictions of the theory of attributional bias, but more research is needed to assess each theory of reading speed.

Evaluation of the effect of viewing distance on visual fatigue in a home viewing environment.

The authors report here the results of evaluation experiments designed to explore the effect of viewing distance on visual fatigue. Two kinds of visual content (normal content and content likely to cause visual fatigue) were used by means of physiological measurements of subject responses while viewing a 42-inch PDP display, followed by psychological evaluations in the form of post-experiment interviews. Both experiments showed that visual fatigue reached a minimum at a distance of 3 to 4 times the height of the display (3-4H; 165 cm-220 cm) and that sympathetic nerve activity peaked at around 3H. These results indicate that the ideal viewing distance for minimal visual fatigue and a closer feeling of involvement might be at around 3H.

[Do patients undergo changes of their personality due to visual field defects? An investigation with FPI-R and NEI-VQ]. / Zeigen Patienten aufgrund ihres Gesichtsfeldausfalls Veränderungen in ihrer Persönlichkeit? Eine Untersuchung mittels FPI-R und NEI-VFQ.

BACKGROUND: Visual restrictions can lead to anxiety and possibly to social retirement. Therefore it makes sense to assess the patients' degree of handicap. The goal of the present study was to investigate if patients show changes in their personality or a reduced quality of life as a result of their visual field defect. METHODS: 15 patients with visual field defects were asked to fill out the revised version of the Freiburger Persönlichkeitsinventar (FPI-R) and the National Eye Institute Visual Function Questionnaire (NEI-VFQ). The FPI-R encompasses the standardised recording of many personality traits whereas the NEI-VFQ addresses the visual quality of life. RESULTS: In the total sample all FPI-R scales were appropriate for the study in the inconspicuous standard range. Slight shifts resulted toward increased willingness to make contacts (scale 4, ST 4.2), reduced physical strain (scale 7, ST 4.3) and lower physical discomfort (scale 8, ST 3.7). The size of the visual field defect does not correlate with the satisfaction with life, with the physical discomfort and with the state of health but with the dependency on others (p = 0.047) and with the exertion of their social roles (p = 0.043). The scale "satisfaction with life" of the FPI-R correlated with the scale "psychic condition" of the NEI-VFQ (p = 0.028) and the physical discomfort showed a significant correlation with the scale "eye strain" (p = 0.006) in the NEI-VFQ. DISCUSSION: Contrary to our presumptions, patients with visual field defects did not show any changes in their personality. It is supposed that they have learned to compensate for their reduced visual functions.

The influence of visual display terminal use on the physical and mental conditions of administrative staff in Japan.

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

Effect of vibration on visual display terminal work performance.

Today electronic visual displays have dramatic use in daily life. Reading these visual displays is subject to their vibration. Using a software-simulation of a vibrated environment, the study investigated the effect of vibration on visual performance and fatigue for several numerical display design characteristics including the font size and the number of digits displayed. Both the frequency and magnitude of vibration had significant effects on the reaction time, accuracy, and visual fatigue. 10 graduate students (23-30 years old; M = 25.6), randomly tested in this experiment, were offered about 25 U.S. dollars for their participation. Numbers in vertical presentation were affected more in vertical vibration than those in horizontal presentation. Analysis showed whenever the display is used in vibration environment, an increased font size may be an effective way to compensate the adverse effect of vibration. The software design of displayed materials must be designed to take the motion effect into consideration to increase the quality of the screen display.

Association between occupational asthenopia and psycho-physiological indicators of visual strain in workers using video display terminals.

BACKGROUND: There is a body of scientific literature examining functional changes in vision due to video display terminals (VDTs). The aim of our study was to determine the relationship of functional visual strain and symptoms of asthenopia and to evaluate the association between subjective and objective indicators of visual strain. MATERIAL/METHODS: Four hundred four office workers with and without involvement in VDT work were included in the study. To evaluate visual strain we used a questionnaire for subjective complaints, evaluated the main ophthalmologic indicators, and measured psycho-physiological indicators. RESULTS: The questionnaire data showed that 88.5% of the VDT workers complained of various vision disorders. VDT workers who complained of worsened vision, redness of the eyes, eye pain, and diplopia during work were found to show more significant changes in the psycho-physiological indicators objectively reflecting strain of the vision analyzer. In the group of people with symptoms of asthenopia, the differences in the indicators of visual sensomotoric reaction, constancy of clear vision, and changes in the periods of clear and unclear vision were statistically reliably greater than in people without symptoms of visual strain. CONCLUSIONS: The subjective perception of visual strain related to VDT work was confirmed by ophthalmologic and psycho-physiological measurements. Changes in ocular and psycho-physiological function before and at the end of the workday are a good objective index of visual and central nervous system strain.

Target spatial frequency determines the response to conflicting defocus- and convergence-driven accommodative stimuli.

Asthenopia, or visual fatigue, is a frequent complaint from observers of stereoscopic three-dimensional displays. It has been proposed that asthenopia is a consequence of anomalous oculomotor responses generated by conflict between accommodative and convergence stimuli. The hypothesis was examined by measuring accommodation and convergence continuously with a Shin-Nippon SRW5000 infrared autorefractor and a limbus tracking device. Subjects viewed a high contrast Maltese Cross target at three levels of Gaussian filter target blur under conditions of relatively low- and high-conflict between accommodation and convergence stimuli, the latter inducing the sensation of stereopsis. Under the low-conflict conditions accommodation was stable, but convergence-driven accommodation was dominant when the target was extremely blurred. Under the high-conflict conditions the role of convergence-driven accommodation increased systematically with the degree of target blur. It is proposed that defocus-driven accommodation becomes weak when the target comprises low spatial frequency components. Large accommodative overshoots to step stimuli that are not blurred or only mildly blurred were consistently observed and are attributed to the initial accommodative response being convergence-driven. Whereas the possibility that high-conflict conditions are a cause of asthenopia has been previously reported, this is the first evidence that they specifically affect accommodative responses while viewing stereoscopic displays.

Ergonomic office design and aging: a quasi-experimental field study of employee reactions to an ergonomics intervention program.

A naturally occurring quasi-experimental longitudinal field study of 87 municipal employees using pretest and posttest measures investigated the effects of an office workstation ergonomics intervention program on employees' perceptions of their workstation characteristics, levels of persistent pain, eyestrain, and workstation satisfaction. The study examined whether reactions differed between younger and older employees. Results revealed that workstation improvements were associated with enhanced perceptions of the workstation's ergonomic qualities, less upper back pain, and greater workstation satisfaction. Among those experiencing an improvement, the perceptions of workstation ergonomic qualities increased more for younger than older employees, supporting the "impressionable years" framework in the psychological literature on aging. Implications for human resources managers are discussed.

Working conditions, visual fatigue, and mental health among systems analysts in São Paulo, Brazil.

AIMS: To evaluate the association between working conditions and visual fatigue and mental health among systems analysts living in São Paulo, Brazil. METHODS: A cross sectional study was carried out by a multidisciplinary team. It included: ergonomic analysis of work, individual and group interviews, and 553 self applied questionnaires in two enterprises. The comparison population numbered 136 workers in different occupations. RESULTS: The study population mainly comprised young males. Among systems analysts, visual fatigue was associated with mental workload, inadequate equipment and workstation, low level of worker participation, being a woman, and subject's attitude of fascination by the computer. Nervousness and intellectual performance were associated with mental workload, inadequate equipment, work environment, and tools. Continuing education and leisure were protective factors. Work interfering in family life was associated with mental workload, difficulties with clients, strict deadlines, subject's attitude of fascination by the computer, and finding solutions of work problems outside work. Family support, satisfaction in life and work, and adequate work environment and tools were protective factors. Work interfering in personal life was associated with subject's attitude of fascination by the computer, strict deadlines, inadequate equipment, and high level of work participation. Satisfaction in life and work and continuing education were protective factors. The comparison population did not share common working factors with the systems analysts in the regression analysis. CONCLUSIONS: The main health effects of systems analysts' work were expressed by machine anthropomorphism, being very demanding, mental acceleration, mental absorption, and difficulty in dealing with emotions.

Visual strain and lighting preferences of VDT users under different lighting systems.

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

Effect of subjective and objective workload on asthenopia at VDU workplaces.

An ergophthalmological tool has been developed to investigate effects of subjective and objective workload on work-related visual complaints (asthenopia). In field studies on different visual display unit (VDU) workplaces effects of objective and subjective workload, work intensity, and work breaks (5-9 min/hour) could be found. It could be shown that during the first hours of VDU work, asthenopic complaints have the tendency to follow effective workload. With increasing working time the effect of a general and visual fatigue overlaps other reported visual complaints in the majority of cases.

A critical appraisal of current knowledge and future directions of ergophthalmology: consensus document of the ICOH Committee on 'Work and Vision'.

In the past, occupational health gave scant attention to the visual apparatus. Studies on issues relating to 'work and vision' have predominantly addressed industrial accidents and the toxic effects of exposure to chemical and physical agents, with secondary prevention being more common than primary prevention. In recent years, the huge transformations implemented in workplaces, mainly due to computer-based technologies, demand a progressively higher efficiency of the eye and the related nervous system components that co-ordinate eye movements and accommodation. At the moment these aspects are managed by medical, psychosocial and a variety of technical disciplines, without any shared criteria, terminology and method. Objectives of the Committee are: to investigate holistically the many possible hazards associated to the occupational visual performance; to come to a consensus on terminology, risk assessment and health surveillance procedures. The present status of research and practice in ergophthalmology does not allow for clear-cut decision about health risk and nor is there a clear direction on the prevention of work-related ocular and visual disturbances and disorders. Specifically, at least three determinants must be objectively considered, namely: (a) visual effort; (b) environmental agents; (c) individual characteristics. Although criteria exist for the evaluation of some of these determinants, a greater refinement is necessary 'for a good working life' of the visual apparatus. The ICOH Scientific Committee on 'Work and Vision' is seeking to systematically develop this matter, yielding a more rational and complete approach to the relationship between work and vision.

Perceptions of occupational hazards amongst office workers at the Obafemi Awolowo University, Ile-Ife.

BACKGROUND: A Survey of 350 office workers at the Obafemi Awolowo University (OAU), Ile-Ife was conducted to determine respondents' perceptions of the occurrence of work-related hazards and to characterize the pattern of hazards found prevalent in the population. METHODS: The survey employed a descriptive cross-sectional design. Data were generated through the use of a structured self-administered questionnaire and a non-participant observation checklist. RESULTS: Between 39% and 47% of the respondents expressed dissatisfaction with the level of control of the factors of the work environment (heat, noise, illumination, space, ergonomics). Two-thirds of respondents presented with work-related low backache, and this was more so for respondents who had spent at least 10 years on the job than those who had spent less. Of the 227 keyboard operators interviewed, 130 (57%) experienced symptoms suggestive of the overuse syndrome and 70% of the 82 computer operators interviewed had experienced varying degrees of visual fatigue since their appointments. CONCLUSION: The study concluded that the present design and layout of offices/workstations and access to equipment at the Obafemi Awolowo University, Ile-Ife is not optimal and tend to promote unnecessary physical efforts. This, in turn, might reduce efficiency and productivity. Suggestions for improvement were made as a way forward.

Office workers and video display terminals: physical, psychological and ergonomic factors.

The purpose of the pilot study was to examine the psychological and physical symptoms reported by video display terminal (VDT) and non-VDT users in relation to intensity and duration of VDT exposure, ergonomic characteristics of the work station, workers' perceptions of the working environments, medical conditions, job satisfaction, and mood states. Thirty VDT users and 16 non VDT users were selected from four departments of a major radiopharmaceutical company for participation in the cross-sectional study. Self-administered questionnaires were utilized to obtain information on symptoms, medical conditions, job satisfaction, mood states, and the working environments. Objective measurements were obtained to provide information on the various ergonomic components of the work station. The study corroborated findings reported in previous studies, whereby eye related symptoms were associated with VDT usage. A higher percentage of symptoms were reported among VDT users even when they had more control over their work stations. These workers expressed higher levels of job satisfaction, and lower levels of tension, fatigue, confusion, anger, and depression than non-VDT users. Most importantly, a trend in symptomatology was identified, whereby symptoms appeared to increase as duration of VDT exposure increased.

Psychological factors and visual fatigue in working with video display terminals.

OBJECTIVES: To examine the part played by psychological factors in complaints about visual health reported by banking officers who work at video display terminals (VDTs). METHODS: Out of a population of 385 bank workers, a group of 212 subjects without organic visual disturbances (as determined by ophthalmological examination) who share a work environment and job duties was selected. Three questionnaires were administered to these subjects: (a) the NIOSH job stress questionnaire; (b) a questionnaire investigating subjective discomfort related to environmental and lighting conditions of the workplace; (c) a questionnaire on the existence of oculovisual disturbances. Correlation and multiple regression analyses were performed to examine for the presence of predictors of asthenopia. RESULTS: Social support, group conflict, self esteem, work satisfaction, and underuse of skills were found to be predictors of visual complaints; social support played a part also as a moderating factor in the stress and strain model; this model accounted for 30% of the variance. Subjective environmental factors, although in some cases significantly correlated with asthenopia, were not found to be strong predictors of the symptoms. CONCLUSIONS: Some part of the complaints about visual health reported by VDT workers are likely indirect expressions of psychological discomfort related to working conditions.

The effects of visual discomfort and pattern structure on visual search.

Unpleasant somatic and perceptual side effects can be induced when viewing striped repetitive patterns, such as a square wave or a page of text. This sensitivity is greater in participants with higher scores on a scale of visual discomfort. In three experiments the effect that this sensitivity has on performance efficiency in a reading-like visual search task was investigated. In experiments 1 and 2, the 'global' structure of the patterns was manipulated to produce a square-wave, a checkerboard, and a plaid pattern. It was found that the group that suffered severe visual discomfort took significantly longer than other groups to perform the task, with interference greatest with presentation of the square-wave-like pattern. This supports the prediction of greatest distraction of visual attention from the local target elements with presentation of the pattern structure inducing greatest visual discomfort. In experiment 3, the internal pattern components were manipulated and task difficulty reduced. A no-interference and two interference patterns, one with a global characteristic only and the second made up of distracting line elements, containing global and local components were used. The global pattern structure produced interference effects on the visual-search task. All groups performed with the same speed and accuracy on the task involving the no-interference pattern, a finding attributed to reduced task difficulty. McConkie and Zola's model of visual attention was used to explain these results.

Evaluation of stereoscopic picture quality with CFF.

The method of binocular stereoscopic imaging has attracted attention as a simple and technically feasible means of three-dimensional (3-D) display. It has been said, however, that the binocular picture system is more fatiguing to view than a conventional two-dimensional picture, much as the current television picture. The main objective of this paper is to evaluate quantitatively fatigue caused by binocular stereoscopic picture viewing, to clarify the basic characteristics of this type of picture. Various measurement methods of fatigue have been proposed, and that using the critical flicker frequency (CFF) has found wide use in measurement of mental fatigue and is easy to make. Actual measurement in this study used the CFF value obtained in a descending series of the method of limits, normalized to the value at the start of measurement for each observer, and the CFFs of all observers then averaged. It was found that the measurements produced stable and highly accurate results. CFFs of the observers of a current television picture and a binocular stereoscopic television picture were measured. It was found that the conventional television did not cause a statistically significant decrease in CFF--even over 1 h of viewing--but that the stereoscopic television did cause a significant CFF decrease within 30 min. It was also found that the CFF decreases are related to a subjective feeling of fatigue. From these results, it was concluded that CFF is an effective measure for objectively measuring the fatigue of television observers, including observers of binocular stereoscopic television. Also, the binocular stereoscopic television produced higher fatigue in observers than did the conventional television picture, but it was found that with respect to CFF viewing of around 30 min was allowable.

Visual accommodation and subject performance during a stereographic object task using liquid crystal shutters.

Virtual reality has become popular in a variety of fields. Three experiments to study visual accommodation and task performance during stereographic vision were carried out in order to better understand the human response to virtual reality. Visual accommodation to stereograms on CRT was studied. Subjects could see the target on the CRT display binocularly through liquid crystal shutters. Accommodation to a stereogram with step changes in distance was tested first. As the second experiment, accommodation to a stereogram with gradual changes in distance, and comparison of ability to perform a colour photograph stereogram task were tested. Finally, accommodation and subject performance during a prolonged stereographic object task were observed for 30 min. A virtual 'gate' was formed at a position 1.2m from the subject. The virtual target moved forward and backward through this gate between the positions of 0.8m and 2.0m. The subjects were asked to focus on the target and press a button as it moved through the virtual gate. Subjective response to the task and the error between the position where the button was pressed and the gate was recorded. It was concluded that there are some people who exhibit large changes in accommodation while performing a stereographic task. There is a tendency to accommodate to a distance nearer than the baseline. Prolonged stereoscopic viewing caused visual fatigue or loss of accommodation and diminished task performance.