Visual Display Unit Research Articles

Comparison of Amplitude of Accommodation in Different Room Illumination while Using VDU as a Target

Purpose: To compare the measurement of the amplitude of accommodation (AA) in different room illumination while using visual display unit (VDU) as a target. Method: A non-randomized, cross-sectional study includes 32 Malaysians aged between 15 to 35 years despite races and gender. Convenience sampling method was used. The data were analyzed by using one-way repeated measure ANOVA, to investigate the changes in the amplitude of accommodation in a different level of illuminations (23 Lux, 17 Lux, and 4 Lux). Result: 32 subjects’ data were analyzed. The amplitude of accommodation measured via a minus-lens method. No significant change has been observed among three levels of room illumination (p>0.05) with the mean difference of 0.222DS from the first room illumination to third room illumination. Furthermore, the association of AA among genders, age groups, race and refractive error for different levels of room illumination was not significant (p>0.05). However, an amplitude of accommodation between 15-21years and 22-28 years showed significant (p=0.047) difference in the first level of room illumination. Conclusion: The level of illumination has no clinically significant effect on the amplitude of accommodation. Key Words: Amplitude of Accommodation, room illumination, visual display unit (VDU), minus lens method

Effect of Illumination over Positive Fusional Vergence when Using VDU as Target

Background: To find out the changes in the positive fusional vergence at near, under different room illuminations while using VDU (Visual Display Unit) as a target. Method: A cross sectional study was performed by using convenience sampling method. The study subjects comprised of 33 Malaysians aged between 15 to 35 years regardless of race and gender. This research was done within a period of six months (April 2015 to September 2015) at Twintech vision clinic. The data were analyzed by using a repeated measure Friedman Test to investigate the changes in positive fusional vergence at near under different room illuminations. Result: 33 subject’s data were analyzed, out of which 17 male and 16 female. Positive fusional vergence at near changed significantly in three different levels of room illumination (p=0.012, p=0.003 and p=0.006 for Blur, Break and Recovery respectively). However, positive fusional vergence between gender was not significant (p>0.05). Conclusion: There is a statistically significant difference in positive fusional vergence for near under different level of illuminations. Moreover, under low illumination the positive fusional vergence seems to be higher. There is no significant difference observed between genders for positive fusional vergence at near.

Analysis of relationships between the use of visual display terminals, craniocervical angle and physical activity: A pilot study

Grounds: The neck posture alterations can cause cervical pain and implicitly produce changes in the neck movement patterns, resulting in a greater risk of musculoskeletal disorders of the neck. The forward head position implies bending of the lower cervical spine and extension of the upper cervical spine. This is a common clinical observation in patients who have a sore neck and shoulders. The main objective of the study is to identify the relationship between the posture, the use of visual display units and physical activity in young adults. Method: This is a descriptive correlational study with a crossover design, with a sample of 26 university students. Data were collected from an ad-hoc questionnaire, physical activity habits questionnaire (SHRI) and a photogrammetry test processed by the postural assessment software (PAS). Results: Statistically significant differences were obtained between physical activity and the craniocervical angle (p = .007) and between the performance of physical activity of students pursuing different university degrees (p = .000). Conclusions: The practice of physical activity of moderate intensity can be a preventive factor for the forward head position.

Work with visual display units and musculoskeletal disorders: A cross-sectional study.

Epidemiological studies have shown that employees working with visual display units (VDU) are more likely to complain about musculoskeletal disorders (MSDs). The aim of this study has been to evaluate associations among MSDs and individuals and work-related factors. A total of 1032 VDU workers were assessed about their personal (i.e., age, working history, smoking history, physical activity) and work-related factors (i.e., predominant job tasks performed, work posture). Work environment was evaluated regarding fulfillment of the standard ISO 9241-5:1998. The investigation required a direct observation of participants (in order to accurately assess the prevalence of MSDs) and workstations. Adjusted odds ratios (ORa) were calculated by means of the logistic regression model. Prevalence of MSDs was relatively high (53%). In general, MSDs were significantly associated with female sex (OR = 2.832, 95% confidence interval (CI): 2.178-3.683), age ≥ 50 years old (OR = 2.231, 95% CI: 1.236-4.026), longer exposure to VDU, both as working history (10-14 years: OR = 1.934, 95% CI: 1.301-2.875; ≥ 15 years: OR = 2.223, 95% CI: 1.510-3.271) and working time (30-39 h/week: OR = 1.537, 95% CI: 1.087-2.273). Inappropriate workstation design was confirmed by the multivariate analysis as a risk factor for MSDs (ORa = 2.375, 95% CI: 1.124-5.018). Musculoskeletal disorders were significantly associated with individual factors as well as characteristics of work environment. An appropriate design of workstations may significantly reduce their prevalence amongst VDU workers. Med Pr 2016;67(6):707-719.

Prevalence and associated factors of myopia among high school students in Gondar town, northwest Ethiopia, 2016.

IntroductionMyopia is an important cause of correctable visual impairment and preventable blindness worldwide. Prevalence rates are approximately 20%–35% among the older teenage population globally. It has a medical burden of pathologic complications such as maculopathy and glaucomatous optic neuropathy. High school students experience high-performance and study pressures in the preparation for the final national examination. As a result they are exposed to excessive near work and indoor activities. They are also ignored for regular screening.ObjectiveTo determine the prevalence and associated factors of myopia among high school students in Gondar town, Ethiopia.MethodsAn institution-based cross-sectional study was conducted on 498 high school students with systematic random sampling method from April 18 to April 29, 2016, in three full-cycle high schools (9th–12th grades). A standardized structured questionnaire, Snellen acuity chart, pinhole, retinoscope, trial case lenses, pen torch, and direct ophthalmoscope were used to collect data.ResultsA total of 495 study participants were included, and they had a mean age of 17.48±1.59 years. The prevalence of myopia was 11.9% (95% confidence interval [CI]: 10.2, 17.9). Family history of myopia (adjusted odds ratio [AOR]=8.08 [95% CI: 4.30, 15.16]), school being private (AOR=2.88 [95% CI: 1.02, 8.11]), longer time spent for near work (AOR=2.89 [95% CI: 1.12, 7.43]), longer time spent partaking in indoor activities (AOR=4.32 [95% CI: 1.69, 10.99]), shorter near working distance (AOR=3.06 [95% CI: 1.33, 7.06]), lack of outdoor sport activities (AOR=2.27 [95% CI: 1.05, 4.90]), use of visual display units (AOR=2.81 [95% CI: 1.30, 6.10]), and abnormal ocular findings (AOR=6.69 [CI: 3.43, 13.03]) were found to be independently associated with myopia.ConclusionThe prevalence of myopia was 11.9%. Family history for myopia, school being private, longer time spent partaking in indoor activities, shorter working distance, lack of outdoor sport activities, use of visual display units, and presence of abnormal ocular findings were positively associated with myopia.

Personal risk factors for carpal tunnel syndrome in female visual display unit workers.

Carpal tunnel syndrome (CTS) is the most common nerve entrapment syndrome, which since the beginning of the seventies has been linked to the keyboard and visual display unit (VDU). The objective of this study was to investigate the prevalence and personal factors associated with CTS in female VDU workers in Italy. Participants in this study were female adult subjects, working ≥ 20 h/week (N = 631, mean age 38.14±7.81 years, mean working age 12.9±7.24 years). Signs and symptoms were collected during compulsory occupational medical surveillance. The binary logistic regression was used to estimate adjusted odds ratios for the factors of interest. Diagnosis of CTS was reported in 48 cases (7.6%, 11 of them or 1.7% after a surgical correction) for the incidence of 5.94/1000 person-years. In general, signs and symptoms of CTS were associated with the following demographic factors: previous trauma of upper limb (adjusted odds ratio (ORa) = 8.093, 95% confidence interval (CI): 2.347-27.904), history (> 5 years) of oral contraceptives therapy/hormone replacement therapy (ORa = 3.77, 95% CI: 1.701-8.354) and cervical spine signs/symptoms (ORa = 4.565, 95% CI: 2.281-9.136). The prevalence of CTS was similar to the estimates for the general population of Italy. Among personal risk factors, hormone therapy, previous trauma of the upper limb and signs/symptoms of the cervical spine appeared to be associated with a higher risk of CTS syndrome. Eventually, the results reinforce interpretation of CTS in VDU workers as a work-related musculoskeletal disorder rather than a classical occupational disease. Int J Occup Med Environ Health 2016;29(6):927-936.

External eye symptoms in indoor environments.

Eye irritation, for example dry or irritated eyes, is generally among top three reported symptoms in office-like environments, in particular among workplaces with cognitive demanding visual display unit (VDU) work. The symptoms are especially among middle and advanced ages and particularly among women more than men. The symptoms are also among the most commonly reported complaints in the eye clinic. To be in a position to interpret the high prevalence of eye symptoms, a multidisciplinary and integrated approach is necessary that involves the external eye physiology (separate from internal eye effects), eye diseases (evaporative dry eye (DE), aqueous-deficient DE, and gland dysfunctions), and risk factors that aggravate the stability of precorneal tear film (PTF) resulting in hyperosmolarity and initiation of inflammatory reactions. Indoor environmental, occupational and personal risk factors may aggravate the PTF stability; factors such as age, contact lenses, cosmetics, diet, draft, gender, low humidity and high temperature, medication, outdoor and combustion pollutants, and VDU work. Psychological stressors may further influence the reporting behavior of eye symptoms. The impact of the risk factors may occur in a combined and exacerbating manner.

Pollutant exposures and health symptoms in aircrew and office workers: Is there a link?

Sensory effects in eyes and airways are common symptoms reported by aircraft crew and office workers. Neurological symptoms, such as headache, have also been reported. To assess the commonality and differences in exposures and health symptoms, a literature search of aircraft cabin and office air concentrations of non-reactive volatile organic compounds (VOCs) and ozone-initiated terpene reaction products were compiled and assessed. Data for tricresyl phosphates, in particular tri-ortho-cresyl phosphate (ToCP), were also compiled, as well as information on other risk factors such as low relative humidity.A conservative health risk assessment for eye, airway and neurological effects was undertaken based on a “worst-case scenario” which assumed a simultaneous constant exposure for 8h to identified maximum concentrations in aircraft and offices. This used guidelines and reference values for sensory irritation for eyes and upper airways and airflow limitation; a tolerable daily intake value was used for ToCP. The assessment involved the use of hazard quotients or indexes, defined as the summed ratio(s) (%) of compound concentration(s) divided by their guideline value(s).The concentration data suggest that, under the assumption of a conservative “worst-case scenario”, aircraft air and office concentrations of the compounds in question are not likely to be associated with sensory symptoms in eyes and airways. This is supported by the fact that maximum concentrations are, in general, associated with infrequent incidents and brief exposures. Sensory symptoms, in particular in eyes, appear to be exacerbated by environmental and occupational conditions that differ in aircraft and offices, e.g., ozone incidents, low relative humidity, low cabin pressure, and visual display unit work. The data do not support airflow limitation effects. For ToCP, in view of the conservative approach adopted here and the rareness of reported incidents, the health risk of exposure to this compound in aircraft is considered negligible.

Finnish discourses of the stakeholders on development of the implementation of EU legislation concerned with occupational safety and health in computer work

The overall research objective was to empirically develop the ideas around a system of occupational safety and health (OSH) practices in visual display unit (VDU) work, to describe their relationship with the OSH legislation and to explore how these best practices work to achieve positive results. The aim of the present study was to explore qualitative perceptions of the stakeholders (Finnish Employers’ Associations, Employees Organizations and OSH Governmental Inspectorates) concerning the way that the OSH legislation on VDU work is being applied at work. Many stakeholders claim that technological advances require that in OSH the VDU legislation should be updated, especially that it should be clarified, e.g., when does the VDU worker have the right to obtain special eyeglasses needed for VDU work. Many stakeholders believe that additional guidelines concerning practical ergonomic arrangements in VDU work environment and eyeglasses of the VDU workers are needed. In VDU ergonomics, the co-operation between workplace and occupational health care professionals needs to be developed.

A Historical Timber Frame Model for Diagnosis and Documentation before Building Restoration

The aim of the project that is described in this paper was to define a four-level timber frame survey mode of a historical building: the so-called “Andlau's Seigniory”, Alsace, France. This historical building was built in the late XVIth century and was in a stage of renovation in order to become a heritage interpretation centre. The used measurement methods combine Total Station measurements, Photogrammetry and 3D Terrestrial Laser scanner. Different modelling workflows were tested and compared according to the data acquisition method, but also according to the characteristics of the reconstructed model in terms of accuracy and level of detail. 3D geometric modelling of the entire structure was performed including modelling the degree of detail adapted to the needs. The described 3D timber framework exists now in different versions, from a theoretical and geometrical one up to a very detailed one, in which measurements and evaluation of deformation by time are potentially allowed. The virtually generated models involving archaeologists, architects, historians and specialists in historical crafts, are intended to be used during the four stages of the project: (i) knowledge of the current state of needs for diagnosis and understanding of former construction techniques; (ii) preparation and evaluation of restoration steps; (iii) knowledge and documentation concerning the archaeological object; (iv) transmission and dissemination of knowledge through the implementation of museum animations. Among the generated models one can also find a documentation of the site in the form of virtual tours created from panoramic photographs before and during the restoration works. Finally, the timber framework model was structured and integrated into a 3D GIS, where the association of descriptive and complementary digital documents was possible. Both offer tools leading to the diagnosis, the understanding of the structure, knowledge dissemination, documentation and the creation of educational activities. The integration of these measurements in a historical information system will lead to the creation of an interactive model and the creation of a digital visual display unit for consultation. It will be offered to any public to understand interactively the art of constructing a Renaissance structure, with detailed photos, descriptive texts and graphics. The 3D digital model of the framework will be used directly in the interpretation path, within the space dedicated to “Seigniory” of Andlau. An interactive touch-screen will be installed. It will incorporate several levels of playgrounds (playful, evocative and teaching). In a virtual way, it will deal with the different stages of building a wooden framework and clarify the art of construction.

The effect of a workstation chair and computer screen height adjustment on neck and upper back musculoskeletal pain and sitting comfort in office workers.

AimsTo assess the effect of a vertical height adjustment of the chair and visual display unit (VDU) on work-related upper quadrant musculoskeletal pain (WRUQMP) and sitting comfort in office workers. The upper quadrant refers to the occiput, cervical and upper thoracic spine, including the clavicles and scapulae.MethodsA single subject (N = 1) study, in which the subject serves as her own control, was conducted using the ABC design. An ergonomic workstation adjustment of VDU and chair height was compared to the subject’s usual workstation settings. Pain and sitting comfort was measured using visual analogue scales (VAS). The subject was assessed over three four-week phases as she performed her typical VDU work. The results were compiled and tabulated.ResultsBoth the mean and variance in pain intensity decreased after the workstation intervention. A deterioration in sitting comfort was noted.ConclusionThe vertical height adjustment of the chair and visual display unit may have contributed to a decrease in work-related upper quadrant musculoskeletal pain in this subject. This safe, economical workstation intervention may be a practical management option for the computer user suffering from work-related upper quadrant musculoskeletal pain. Further research into the measurement of comfort whilst sitting at a computer workstation is recommended.

Ergonomic chair intervention: Effect on chronic upper quadrant dysfunction, disability and productivity in female computer workers

AIM: To compare the effect of two ergonomic chairs on upper quadrant musculoskeletal pain and tension, disability and productivity among female computer workers in the office workplace.METHODS: A series of two N=1 studies were conducted using the A-B-A-C-A design whereby an intervention ergonomic chair was compared to a less adjustable control ergonomic chair using visual analogue scales (VAS) for pain and muscle spasm, the Neck Disability Index and the Work Productivity and Activity Impairment questionnaire. The female participants were assessed over the four week phases as they performed high intensity visual display unit work. The results were compiled and tabulated.RESULTS: Both the control and intervention ergonomic chairs showed a reduction in both the mean and variance of pain and muscle spasm. The second participant also showed an increase in productivity with both chairs.CONCLUSION: The introduction of an ergonomic chair shows a reduction in VAS intensity and frequency for pain and muscle spasm, as well as a reduction in variance of the symptoms. Both chairs showed a similar reduction in symptoms, thus indicating almost equivalent benefit from the use of both ergonomic chairs.

EHMTI-0350. Introducing a novel six-phase method for effective screening of the patients diagnosed with neurological electromagnetic hypersensitivity (EHS)

Background Electromagnetic hypersensitivity (EHS) is a relatively new phenomenon characterized by experiencing neurological symptoms such as headache, dizziness, anxiety, and insomnia after exposure to electromagnetic fields (EMFs) like those generated by mobile phones and visual display units (VDUs). Although some published reports suggest that EHS is unrelated to the presence of electromagnetic fields, the etiology of EHS is not clearly known. Over the past years our lab has been studying the health effects of exposure of laboratory animals and humans to different sources of electromagnetic fields such as mobile phones, mobile base stations, mobile phone jammers, laptop computers, radars, dentistry cavitrons and MRI. Aim In this paper we introduce a novel method for effective screening of the patients diagnosed with EHS. Method

Effects of discomfort glare on performance in attending peripheral visual information in displays

Large screens have become more popular in recent years. Because of the increasing size of displays, the amount of information presented in the peripheral visual field has gained importance in many tasks on visual display units. Users of displays are often exposed to some change or difference in luminance in or between different areas of a display, which in turn may produce a phenomenon known as discomfort glare. Discomfort glare is likely to affect cognitive performance. The performance in the visual periphery is more susceptible to disturbances as is the case for the performance in the central visual field.This study explored the effects of discomfort glare on detecting and processing peripheral visual information in a complex visual task. The task consisted of comparing the orientation of arrows presented in the central visual field and at 18° in the periphery. The arrows were superimposed on a background video and presented by a projection system in virtual reality. 50% of the presentations were preceded by a mild glare scene with a luminance of 25cd/m2 flashed prior to the stimulus. Experimental results of 56 participants were analyzed using the theory of signal detection. A significant difference (two-tailed t-test p=0.01) in detectability of stimuli (d′glare=1.87; d′no glare=2.11; Δd′=0.24) was obtained when comparing the performance in the two situations of glare. Results show that discomfort glare impairs peripheral visual performance in attending stimuli in a virtual reality environment. We therefore propose to consider discomfort glare as a factor affecting performance in detecting peripheral visual information. Discomfort glare should be included as a quality criterion in rating visual information, as is done in present standards of displays and lighting.

Information systems design for coal and ash resources management

This paper propounds a systematic information systems design for the effective management of coal and ash resources, as well as methods to prevent spontaneous heating of stored coal, in the light of some actual experiences with coal stockpile flowslides at an electric power generation station in Asia. Specifically, the paper proposes a methodology consisting of a computer–controlled operating system, complemented by a full management information backup, and utilising a touch screen type input/output visual display unit (VDU), which is code–named SCARM–acronym for Information Systems Design for Coal and Ash Resources Management. This has proven to be a suitable model for the prevention of spontaneous heating of stored coal, as well as for the upgrading of the coal handling plant by means of a stacker/reclaimer, so as to enhance the generating capacity.

Effects of Wink Glass on Blink Rate, Nibut and Ocular Surface Symptoms during Visual Display Unit Use

Purpose/Aim: Wink glass (WG), an invention to stimulate blinking at interval of 5 s was designed to reduce dry eye symptoms during visual display unit (VDU) use. The objective of this study is to investigate the effect of WG on visual functions that include blink rate, ocular surface symptoms (OSS) and tear stability during VDU use.Materials and methods: A total of 26 young and asymptomatic subjects were instructed to read articles in Malay language with a computer for 20 min with WG whereby their blink rate, pre- and post-task tear break-up time, and OSS were recorded. The results were compared to another reading session of the subjects wearing a transparent plastic sheet as a control.Results: Non-invasive tear break-up time was reduced after reading session with transparent plastic sheet (pre-task = 5.97 s, post-task = 5.14 s, z = −2.426, p = 0.015, Wilcoxon), but remained stable (pre-task = 5.62 s, post-task = 5.35 s, z = −0.67, p = 0.501) during the reading session with WG. The blink rate recorded during reading session with plastic sheet was 9 blinks/min (median) and this increased to 15 blinks/min (z = −3.315, p = 0.001) with WG. The reading task caused OSS (maximum scores = 20) with median score of 1 (0–8) reduced to median score of 0 (0–3) after wearing WG (z = −2.417, p = 0.016).Conclusion: WG was found to increase post-task tear stability, increased blinking rate and reduced OSS during video display unit use among young and healthy adults. Although it may be considered as an option to improve dry eye symptoms among VDU users, further studies are warranted to establish its stability and its effect on subjects with dry eyes.

A portable system for identifying urinary tract infection in primary care using a PC-based chromatic technique

An approach is described for monitoring urine samples using a portable system based on chromatic techniques and for predicting urinary tract infection (UTI) from the results. The system uses a webcam–computer combination with the screen of a computer visual display unit as a tuneable illumination source. It is shown that the system can operate in a robust manner under ambient lighting conditions and with potential for use as a point of care test in primary care. The present approach combines information on urine liquid concentration and turbidity. Its performance in an exploratory study is compared with microbiological culture of 200 urine samples, of which 79 had bacterial growth >105 colony forming unit/millilitre (cfu ml−1) indicative of UTI. It is shown that both sensitivity and negative predictive value of 0.92 could be achieved.

Relation between head and eye movement and neck and shoulder complaints in presbyopic VDU users

Purpose In subjects with neck-shoulder complaints at visual display unit (VDU) work places (>4 hours daily) the influence through a multifocal lens design on the head-eye-movement was examined. Materials and methods The head-eye-movement (head-eye-mover ratio horizontal) was determined in 100 presbyopic subjects with the Vision Print® (Essilor). The subjects were randomized and single-blind divided to three different interventions, group I: head-, II: eye-mover design, III: nearwork design, and a control group with no intervention. Results In presbyopic subjects with neck-shoulder discomfort a workstation seams to contribute to the manifestation of the pathological stereotype eye mover in the horizontal gaze shift. With the multifocal lenses a significant reduction in complaints in the shoulder and neck area for the groups I, II and III was found. The change of the head-eye-mover ratio (horizontal) in the direction of increased head movement was shown tendencially in all supplied groups, but not in the co...

An interface redesign for the feed-water system of the advanced boiling water reactor in a nuclear power plant in Taiwan

A well-designed human-computer interface for the visual display unit in the control room of a complex environment can enhance operator efficiency and, thus, environmental safety. In fact, a cognitive gap often exists between an interface designer and an interface user. Therefore, the issue of the cognitive gap of interface design needs more improvement and investigation. This is an empirical study that presents the application of an ecological interface design (EID) using three cases and demonstrates that an EID framework can support operators in various complex situations. Specifically, it analyzes different levels of automation and emergency condition response at the Lungmen Nuclear Power Plant in Taiwan. A simulated feed-water system was developed involving two interface styles. This study uses the NASA Task Load Index to objectively evaluate the mental workload of the human operators and the Situation Awareness Rating Technique to subjectively assess operator understanding and response, and is a pilot study investigating EID display format use at nuclear power plants in Taiwan. Results suggest the EID-based interface has a remarkable advantage over the original interface in supporting operator performance in the areas of response time and accuracy rate under both normal and emergency situations and provide supporting evidence that an EID-based interface can effectively enhance monitoring tasks in a complex environment.

Evolutionary adaptations: Theoretical and practical implications for visual ergonomics

The literature discussing visual ergonomics often mention that human vision is adapted to light emitted by the sun. However, theoretical and practical implications of this viewpoint is seldom discussed or taken into account. The paper discusses some of the main theoretical implications of an evolutionary approach to visual ergonomics. Based on interactional theory and ideas from ecological psychology an evolutionary stress model is proposed as a theoretical framework for future research in ergonomics and human factors. The model stresses the importance of developing work environments that fits with our evolutionary adaptations. In accordance with evolutionary psychology, the environment of evolutionary adaptedness (EEA) and evolutionarily-novel environments (EN) are used as key concepts. Using work with visual display units (VDU) as an example, the paper discusses how this knowledge can be utilized in an ergonomic analysis of risk factors in the work environment. The paper emphasises the importance of incorporating evolutionary theory in the field of ergonomics. Further, the paper encourages scientific practices that further our understanding of any phenomena beyond the borders of traditional proximal explanations.