Preferred position of visual displays relative to the eyes: a field study of visual strain and individual differences

Ergonomics in facial plastic and reconstructive surgery

PURPOSE OF REVIEW

Understanding effective ergonomic interventions is crucial for enhancing occupational health and career longevity. There is a paucity of clear ergonomics guidelines in facial plastic and reconstructive surgery (FPRS), placing practitioners at high risk of work-related musculoskeletal disorders (WMSDs) and their consequences.

RECENT FINDINGS

There is mounting evidence that FPRS specialists are at increased risk of WMSDs as compared with the public and other surgical specialties. Numerous studies have demonstrated that implementation of ergonomics principles in surgery decreases WMSDs. Furthermore, WMSDs are reported as early as the first year of surgical residency, marking the importance of early intervention.

SUMMARY

Fatigue and physical injuries among surgeons occur more often than expected, particularly during complex, extended procedures that necessitate maintaining a constant posture. FPRS procedure often place surgeons into procrustean positions. Thus, integrating ergonomic practices into the practice of FPRS is essential for reducing WMSDs.

Comparing Three-Dimensional Digitally Enabled Intraoperative OCT With Conventional Microscope-Integrated OCT in Vitreoretinal Surgery: A Post Hoc Analysis of the Discover Study

BACKGROUND AND OBJECTIVE

This study compared the surgeon experience between conventional microscope-integrated intraoperative optical coherence tomography (iOCT) and digitally enabled microscope-integrated iOCT in vitreoretinal surgery.

PATIENTS AND METHODS

This is a post hoc case-control analysis of the DISCOVER study. Conventional microscope-integrated iOCT (Rescan 700, Zeiss) was compared with digitally enabled iOCT (Artevo 800, Zeiss). Compared variables included surgical field-based visualization (ie, ocular heads-up display in the conventional group; three-dimensional screen-based visualization in the digital iOCT group) and non-surgical field-based visualization (ie, review on the external two-dimensional monitor).

RESULTS

A total of 200 patients were included. Surgical field-based visualization of iOCT was significantly higher in the digitally enabled group (P < 0.0001). Required endoillumination level was significantly lower in the digital iOCT group (P < 0.0001). Surgeons reported "significant" back discomfort and headache more frequently when using conventional iOCT (P = 0.003 and P = 0.001, respectively).

CONCLUSIONS

Digitally enabled iOCT resulted in greater surgical visualization efficiency, appeared to require a lower illumination level, and may provide advantages for ergonomic-related discomfort. [Ophthalmic Surg Lasers Imaging Retina 2024;55:XX-XX.].

Distraction suppresses high-fat flavor perception

Distraction during eating contributes to overeating, and when habitually eating with distraction, this may contribute to the development of obesity. One of the proposed mediating mechanisms is the suppression of intensity perception in odor and taste. The effect of distraction on fat intensity perception in flavor, the multisensory combination of odor, taste, and other sensory aspects, is still unknown. In this study, 32 participants (22 women) performed a flavor perception task while also performing a distracting working memory task. In each trial, participants were instructed to observe and memorize a string of 3 (low cognitive load) or 7 (high cognitive load) consonants. Then they received a small quantity of a high- or low-fat chocolate drink, and after that, they were asked to select the string they tried to memorize from three answer options. Last, they rated the intensity and fattiness of the flavor. As intended, in the working memory task, we observed that with a high cognitive load (relative to a low cognitive load), accuracy decreased and response times increased. Regarding perception of the flavors, we observed that overall, high-fat drinks were rated as more intense and fattier. Cognitive load and fat content interacted, such that for the low-fat drink, intensity and fattiness ratings were similar under both cognitive loads; however, under the high cognitive load (relative to the low cognitive load), intensity and fattiness ratings for the high-fat drink were lower. Our results show that distraction can impact the perception of fat in high-fat drinks. If distraction primarily reduces perception of high-fat foods, this may pose a particular risk of overeating high-calorie foods.

Don't Just Stand There. Rethinking the Ideal Body Posture for Otorhinolaryngologists

Surgeons have a high rate of work-related musculoskeletal injuries; an area that has received little attention. These injuries result in surgeons performing less efficiently, needing to take time off work, suffering higher rates of burnout, and may ultimately lead surgeons to retire earlier than planned. Otorhinolaryngologists are at particular risk for work-related musculoskeletal injuries. Beyond the clinician, sustaining such injuries can negatively impact patient safety. Ergonomic interventions have been used effectively to reduce work-related musculoskeletal injuries in other professions, yet not in surgery. With traditional teachings of ideal body postures to avoid injury and manual handling training being re-evaluated, it is important to explore evidence based interventions for reducing work-related musculoskeletal injuries in otorhinolaryngologists. New research encourages us to shift the focus away from the traditional one-size-fits-all approach to ergonomics and toward postural recommendations and education that promote a dynamic, individualized approach to avoiding sustained, static and awkward postures.

Impact assessment of e-trainings in occupational safety and health: a literature review

BACKGROUND

Implementing workplace preventive interventions reduces occupational accidents and injuries, as well as the negative consequences of those accidents and injuries. Online occupational safety and health training is one of the most effective preventive interventions. This study aims to present current knowledge on e-training interventions, make recommendations on the flexibility, accessibility, and cost-effectiveness of online training, and identify research gaps and obstacles.

METHOD

All studies that addressed occupational safety and health e-training interventions designed to address worker injuries, accidents, and diseases were chosen from PubMed and Scopus until 2021. Two independent reviewers conducted the screening process for titles, abstracts, and full texts, and disagreements on the inclusion or exclusion of an article were resolved by consensus and, if necessary, by a third reviewer. The included articles were analyzed and synthesized using the constant comparative analysis method.

RESULT

The search identified 7,497 articles and 7,325 unique records. Following the title, abstract, and full-text screening, 25 studies met the review criteria. Of the 25 studies, 23 were conducted in developed and two in developing countries. The interventions were carried out on either the mobile platform, the website platform, or both. The study designs and the number of outcomes of the interventions varied significantly (multi-outcomes vs. single-outcome). Obesity, hypertension, neck/shoulder pain, office ergonomics issues, sedentary behaviors, heart disease, physical inactivity, dairy farm injuries, nutrition, respiratory problems, and diabetes were all addressed in the articles.

CONCLUSION

According to the findings of this literature study, e-trainings can significantly improve occupational safety and health. E-training is adaptable, affordable, and can increase workers' knowledge and abilities, resulting in fewer workplace injuries and accidents. Furthermore, e-training platforms can assist businesses in tracking employee development and ensuring that training needs are completed. Overall, this analysis reveals that e-training has enormous promise in the field of occupational safety and health for both businesses and employees.

Radiology blues: Comparing occupational blue-light exposure to recommended safety standards

Background

The blue-light hazard is a well-documented entity addressing the detrimental health effects of high-energy visible light photons in the range of 305 nm - 450 nm. Radiologists spend long hours in front of multiple light-emitting diode (LED)-based diagnostic monitors emitting blue light, predisposing them to potentially higher blue-light dosages than other health professionals.

Objectives

The authors aimed to quantify the blue light that radiology registrars are exposed to in daily viewing of diagnostic monitors and compared this with international occupational safety standards.

Method

A limited cross-sectional observational study was conducted. Four radiology registrars at two academic hospitals in Bloemfontein from 01 October 2021 to 30 November 2021 participated. Diagnostic monitor viewing times on a standard workday were determined. Different image modalities obtained from 01 June 2019 to 30 November 2019 were assessed, and blue-light radiance was determined using a spectroscope and image analysis software. Blue-light radiance values were compared with international safety standards.

Results

Radiology registrars spent on average 380 min in front of a diagnostic display unit daily. Blue-light radiance from diagnostic monitors was elevated in higher-intensity images such as chest radiographs and lower for darker images like MRI brain studies. The total blue-light radiance from diagnostic display units was more than 10 000 times below the recommended threshold value for blue-light exposure.

Conclusion

Blue-light radiance from diagnostic displays measured well below the recommended values for occupational safety. Hence, blue-light exposure from diagnostic monitors does not significantly add to the occupational health burden of radiologists.

Contribution

Despite spending long hours in front of diagnostic monitors, radiologists' exposure to effective blue-light radiance from monitors was far below hazardous values. This suggests that blue-light exposure from diagnostic monitors does not increase the occupational health burden of radiologists.

Social Media Devices' Influence on User Neck Pain during the COVID-19 Pandemic: Collaborating Vertebral-GLCM Extracted Features with a Decision Tree

The prevalence of neck pain, a chronic musculoskeletal disease, has significantly increased due to the uncontrollable use of social media (SM) devices. The use of SM devices by younger generations increased enormously during the COVID-19 pandemic, being-in some cases-the only possibility for maintaining interpersonal, social, and friendship relationships. This study aimed to predict the occurrence of neck pain and its correlation with the intensive use of SM devices. It is based on nine quantitative parameters extracted from the retrospective X-ray images. The three parameters related to angle_1 (i.e., the angle between the global horizontal and the vector pointing from C7 vertebra to the occipito-cervical joint), angle_2 (i.e., the angle between the global horizontal and the vector pointing from C1 vertebra to the occipito-cervical joint), and the area between them were measured from the shape of the neck vertebrae, while the rest of the parameters were extracted from the images using the gray-level co-occurrence matrix (GLCM). In addition, the users' ages and the duration of the SM usage (H.mean) were also considered. The decision tree (DT) machine-learning algorithm was employed to predict the abnormal cases (painful subjects) against the normal ones (no pain). The results showed that angle_1, area, and the image contrast significantly increased statistically with the time of SM-device usage, precisely in the range of 2 to 9 h. The DT showed a promising result demonstrated by classification accuracy and F1-scores of 94% and 0.95, respectively. Our findings confirmed that the objectively detected parameters, which elucidate the negative impacts of SM-device usage on neck pain, can be predicted by DT machine learning.

Digital Eye Strain- A Comprehensive Review

Digital eye strain (DES) is an entity encompassing visual and ocular symptoms arising due to the prolonged use of digital electronic devices. It is characterized by dry eyes, itching, foreign body sensation, watering, blurring of vision, and headache. Non-ocular symptoms associated with eye strain include stiff neck, general fatigue, headache, and backache. A variable prevalence ranging from 5 to 65% has been reported in the pre-COVID-19 era. With lockdown restrictions during the pandemic, outdoor activities were restricted for all age groups, and digital learning became the norm for almost 2 years. While the DES prevalence amongst children alone rose to 50-60%, the symptoms expanded to include recent onset esotropia and vergence abnormalities as part of the DES spectrum. New-onset myopia and increased progression of existing myopia became one of the most significant ocular health complications. Management options for DES include following correct ergonomics like reducing average daily screen time, frequent blinking, improving lighting, minimizing glare, taking regular breaks from the screen, changing focus to distance object intermittently, and following the 20-20-20 rule to reduce eye strain. Innovations in this field include high-resolution screens, inbuilt antireflective coating, matte-finished glass, edge-to-edge displays, and image smoothening graphic effects. Further explorations should focus on recommendations for digital screen optimization, novel spectacle lens technologies, and inbuilt filters to optimize visual comfort. A paradigm shift is required in our understanding of looking at DES from an etiological perspective, so that customized solutions can be explored accordingly. The aim of this review article is to understand the pathophysiology of varied manifestations, predisposing risk factors, varied management options, along with changing patterns of DES prevalence post COVID-19.

Improving office workers’ workspace using a self-adjusting computer screen

With the rapid evolution of technology, computers and their users’ workspaces have become an essential part of our life in general. Today, many people use computers both for work and for personal needs, spending long hours sitting at a desk in front of a computer screen, changing their pose slightly from time to time. This phenomenon impacts people’s health negatively, adversely affecting their musculoskeletal and ocular systems. To mitigate these risks, several different ergonomic solutions have been suggested. This study proposes, demonstrates, and evaluates a technological solution that automatically adjusts the computer screen position and orientation to its user’s current pose, using a simple RGB camera and robotic arm. The automatic adjustment will reduce the physical load on users and better fit their changing poses. The user’s pose is extracted from images continuously acquired by the system’s camera. The most suitable screen position is calculated according to the user’s pose and ergonomic guidelines. Thereafter, the robotic arm adjusts the screen accordingly. The evaluation was done through a user study with 35 users who rated both the idea and the prototype system itself highly.

The effect of vertical gaze position on ocular tear film stability

BACKGROUND

An enlarged exposed ocular surface area is known to degrade tear film stability. Little is known of how tear film stability alters with vertical gaze and the change of palpebral fissure height.

METHODS

Tear film break-up time (TBUT; fluorescent dye) and palpebral fissure height were measured in three vertical gaze positions (primary position and 20 degrees up and 20 degrees down) on 23 healthy volunteers. The effect of gaze direction on TBUT was analysed by ANOVA.

RESULTS

Gaze had a significant influence on tear film stability [F(2,44)=27.6, p<0.001]. In up-gaze with an enlarged palpebral fissure height (11.1 +/- 1.4 mm), TBUT was degraded (17.3 +/- 12.7 seconds). In down-gaze and decreased palpebral fissure height (6.7 +/- 1.2 mm) TBUT was extended (43.5 +/- 35.4 seconds).

CONCLUSION

Ocular tear film stability alters with vertical gaze. Our hypothesis is that the change of the palpebral fissure height and the exposed ocular surface area alters the thickness of the lipid layer and with it tear film evaporation.

Conventional Microscope-Integrated Intraoperative OCT Versus Digitally Enabled Intraoperative OCT in Vitreoretinal Surgery in the DISCOVER Study

BACKGROUND AND OBJECTIVE

To compare conventional microscope-integrated intraoperative optical coherence tomography (iOCT) and digitally enabled microscope-integrated iOCT in vitreoretinal surgery.

PATIENTS AND METHODS

In this post-hoc analysis of the DISCOVER prospective iOCT study, two surgical groups were compared: (1) conventional iOCT and (2) digitally enabled iOCT. Surgeon questionnaires were collected immediately following surgery.

RESULTS

A total of 187 subjects were included in the study: 91 in the conventional iOCT group and 96 in the digitally enabled iOCT group. There were no differences in surgeon-perceived iOCT utility between the two groups. There was significantly higher surgical field-based visualization of the iOCT datastream in the digitally enabled iOCT group (67.7% vs. 3.3%; P < .0001). Reported significant back discomfort (1.0% vs. 18.7%; P < .0001) and headaches (5.2% vs. 20.9%; P < .002) were lower in the digitally enabled iOCT group.

CONCLUSIONS

Feasibility and utility of iOCT were similar in both groups. Digitally enabled iOCT datastream enabled increased attention on the surgical field during OCT review. [Ophthalmic Surg Lasers Imaging Retina. 2020;51:S37-S43.].

Computer vision syndrome and its associated ergonomic factors among bank workers

Objectives. This study aimed to describe the prevalence of ergonomic factors associated with computer vision syndrome (CVS), and knowledge and practices of computer usage among bank workers in the Cape Coast Metropolis, Ghana. Methods. A comprehensive eye examination was performed for 139 bankers in the Cape Coast Metropolis. Measurements of ergonomic practices at workstations were carried out and self-administered questionnaires were used to collect socio-demographic data, symptoms of CVS and associated factors as well as knowledge, attitudes and practices of the bankers on CVS. Descriptive statistics and logistic regression were carried out to compute the different proportions and relevant associations. Results. Headaches (73.4%), eyestrain (65.5%) and itching (63.3%) were the most common reported symptoms. The prevalence of CVS in the study population was 71.2% with a high level of poor ergonomic practices (78.4%) at computer workstations. With regard to knowledge, attitudes and practices of the participants on CVS, 68.3% of the participants had low levels of knowledge on CVS, while 90.6% had negative attitudes towards CVS and 46.0% of the participants had poor practices. Conclusion. Bankers had a high prevalence of CVS. Ergonomic practices, females and computer usage were all associated significantly with the presence of CVS.

An Evidence-Based Strategic Approach to Prevention and Treatment of Dry Eye Disease, a Modern Global Epidemic

Dry eye disease (DED) is an emerging health concern causing significant visual, psychological, social, and economic impact globally. In contrast to visual rehabilitation undertaken at late stages of DED, measures instituted to prevent its onset, establishment, or progression can alter its natural course and effectively bring down the associated morbidity. This review attempts to present the available literature on preventive strategies of DED at one place, including strategies for risk assessment and mitigation, targeting a wide range of population. A literature search was conducted using PubMed and an extensive literature review on preventive strategies for DED was compiled to put forth a holistic and strategic approach for preventing DED. This can be undertaken at various stages or severity of DED directed at different tiers of the health care system. Conclusion: This review intends to put emphasis on preventive strategies being adopted as an integral part of routine clinical practice by general ophthalmologists and specialists to tackle the burden of DED and improve the quality of the lives of the patients suffering from it.

Digital Eye Strain Epidemic amid COVID-19 Pandemic - A Cross-sectional Survey

Purpose: There has been an enormous increase in the use of gadgets for online classes and entertainment during the COVID-19 pandemic. This study aimed to estimate the prevalence of digital eye strain (DES), describe the pattern of gadget usage, and analyse the risk factors for DES.Methods: This online survey analysed 941 responses from students of online classes (688), teachers of online classes (45), and general population (208). A pre-validated questionnaire was used to calculate the DES score. Non-parametric tests of medians were used to compare the median DES score, Chi-square test to compare categorical variables, and binary logistic regression to find the predictors of DES.Results: The prevalence of eye strain was higher among students taking online classes compared to the general public (50.6% vs 33.2%; χ² = 22.5, df = 1, p < .0001). There was an increase in screen time during the pandemic compared to pre-pandemic time. The DES score was highest among students attending online classes (p < .0001), in those with eye diseases (p = .001), greater screen time (p = <0.0001), screen distance <20 cm (p = .002), those who used gadgets in dark (p = .017) and those who took infrequent/no breaks (p = .018). The DES scores were proportional to the increase in the number of hours of gadget usage during the pandemic.Conclusion: There is a need to educate people about limiting overall screen exposure and ergonomic methods of screen viewing. Efforts from policymakers to reduce the duration of online classes for students and online work hours for professionals are warranted to control this epidemic of eye strain.

Digital Screen Use and Dry Eye: A Review

Prolonged and continuous daily use of digital screens, or visual display terminals (VDTs), has become the norm in occupational, educational, and recreational settings. An increased global dependence on VDTs has led to a rise in associated visual complaints, including eye strain, ocular dryness, burning, blurred vision, and irritation, to name a few. The principal causes for VDT-associated visual discomfort are abnormalities with oculomotor/vergence systems and dry eye (DE). This review focuses on the latter, as advances in research have identified symptomology and ocular surface parameters that are shared between prolonged VDT users and DE, particularly the evaporative subtype. Several mechanisms have been implicated in VDT-associated DE, including blink anomalies, damaging light emission from modern devices, and inflammatory changes. The presence of preexisting DE has also been explored as an inciting and exacerbating factor. We review the associations between digital screens and DE, mechanisms of damage, and therapeutic options, hoping to raise awareness of this entity with the goal of reducing the global morbidity and economic impact of screen-associated visual disability.

Video Display Operator Complaints: A 10-Year Follow-Up of Visual Fatigue and Refractive Disorders

Visual fatigue and discomfort are very common complaints for video display operators (VDTs). The aim of our study was to study work-related visual symptoms in relation to refractive disorders and psychosocial factors in 3054 public employees by way of follow-ups for 10 years with periodic medical examinations with eye evaluation in the period 2000-2009. Factors related to visual fatigue were evaluated in the follow-up using generalized equation estimation. Visual fatigue was very common in VDT operators (64.03%). During the follow-up, no relationship between visual fatigue and age, sex, seniority of work, visual acuity and refractory disorders was found. Visual fatigue was significantly associated with anxiety perception in a dose-related matter (odds ratio (OR) 7.40, confidence interval (CI) 95% 1.77-31.3), psychosocial factors (OR 1.03, CI 95% 1.01-1.07), use of lenses (OR 1.34, CI 95% 1.09-1.64) and time of VDT usage (OR 1.27, CI 95% 1.04-1.53). This study confirmed that visual fatigue is common in VDT users and is related to anxiety perception, time of VDT usage, use of lenses and stress. No relationship was found between visual fatigue and refractory disorders or visual acuity.

[Semi-quantitative ergonomic analysis of the biomechanical constraints within the cervical spine among screen-operators in the Tunisian universities]

Introduction

Evaluer les contraintes biomécaniques associées aux cervicalgies parmi les opérateurs sur écran.

Méthodes

Etude ergonomique réalisée au prés de 325 opérateurs sur écran dans 25 établissements de l’université du centre tunisien, basée sur une étude anthropométrique du poste du travail sur écran et une analyse semi-quantitative sur des enregistrements vidéo des activités des travailleurs conduits sur une période représentative de 30 minutes.

Résultats

La prévalence des cervicalgies évaluée à 72,3%, a concerné une population de travailleurs qui exerçait avec un siège et un plan de travail inadaptés (84,6%) et un écran bas situé par rapport au regard horizontal (81,2%). L’analyse semi-quantitative par enregistrement vidéo du poste de travail a conclu que la nuque était maintenue en flexion franche de plus de 40 degrés sur 69% du temps global du travail. La flexion latérale a été visible sur 50,3% du temps de travail et la rotation droite ou gauche sur 57,4% du temps de travail. Ainsi, Les opérations de prise d’information de l’écran, de regard du clavier et de consultation des documents se sont dégagées comme les plus de contraignantes pour la nuque sur le plan gestuel et postural.

Conclusion

Nos résultats mettent en évidence l’importance des contraintes biomécaniques associées à la conception du poste de travail sur écran non conforme aux dimensions anthropométriques ergonomiquement recommandées. Ces contraintes sont associées à une prévalence élevée des cervicalgies traduisant la nécessité d’aménagement ergonomique de ces postes de travail pour prévenir ce fléau.

Computer Vision Syndrome: Darkness Under the Shadow of Light

Radiologists typically spend long hours staring at the computer monitor. This unavoidable nature of our work can lead to detrimental effects on the eyes. Moreover, there is little awareness among radiologists with regards to such potential harm. Ocular hazards, such as computer vision syndrome, are increasingly becoming more relevant to the radiology community. In this article, we discuss the ocular occupational hazards faced by radiologists and suggestions that may help in minimizing such hazards.

Master-slave motion alignment for an open surgical console

BACKGROUND

Open surgical consoles widely employed in minimally invasive surgery have better ergonomics than closed consoles. To enhance surgical robots' ergonomics, operational efficiency, and safety, an effective master-slave motion alignment model should be established.

METHODS

The kinematic model of the robot system based on laparoscopic camera coordinate system is built in the first place. Then, the relative pose between the operator's eyes and the display is measured by Tobii Eye Tracking Sensor and is subsequently used to improve the master-slave motion alignment model.

RESULTS

Robot threading experiments are conducted by two doctors and three testers to verify the kinematic model. As a result, in contrast to the original model, the improved model reduces both operation time and the number of collisions.

CONCLUSIONS

The improved master-slave motion alignment model, in which the transformation matrix between the operator's eyes and the display is employed, raises the ergonomics, operational efficiency, and safety.

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.

Effects of touch target location on performance and physical demands of computer touchscreen use

Touchscreen interfaces for computers are known to cause greater physical stress compared to traditional computer interfaces. The objective of this study was to evaluate how physical demands and task performance of a tap gesture on a computer touchscreen vary between target locations and display positions. Twenty-three healthy participants conducted reach-tap-return trials with touch targets at fifteen locations in three display positions. Mean completion time, touch accuracy and electromyography of the shoulder and neck extensor muscles were compared between the target locations and display positions. The results demonstrated that participants completed the trial 12%-27% faster with 13%-39% less muscle activity when interacting with targets in the lower area of the display compared to when tapping upper targets (p < 0.05). The findings suggest that proper target placement and display positioning can improve task performance and lessen physical demands of computer touchscreen interface use.

Effects of display curvature, display zone, and task duration on legibility and visual fatigue during visual search task

This study examined the effects of display curvature (400, 600, 1200 mm, and flat), display zone (5 zones), and task duration (15 and 30 min) on legibility and visual fatigue. Each participant completed two 15-min visual search task sets at each curvature setting. The 600-mm and 1200-mm settings yielded better results than the flat setting in terms of legibility and perceived visual fatigue. Relative to the corresponding centre zone, the outermost zones of the 1200-mm and flat settings showed a decrease of 8%-37% in legibility, whereas those of the flat setting showed an increase of 26%-45% in perceived visual fatigue. Across curvatures, legibility decreased by 2%-8%, whereas perceived visual fatigue increased by 22% during the second task set. The two task sets induced an increase of 102% in the eye complaint score and a decrease of 0.3 Hz in the critical fusion frequency, both of which indicated an increase in visual fatigue. In summary, a curvature of around 600 mm, central display zones, and frequent breaks are recommended to improve legibility and reduce visual fatigue.

A Survey of Work-Related Musculoskeletal Disorders Among Otolaryngologists

There are increased reports of prevalence of work-related musculoskeletal disorders (WRMSDs) in surgeons performing minimal access surgeries. Due to the nature of the speciality, otolaryngologists spend their work days in performing markedly precise procedures in small workspaces i.e. the patients' ear, nose and throat. Due to this, they frequently adopt awkward neck, back and shoulder postures while using devices like otoscope, endoscope and microscope. The field of otolaryngology has barely received any attention with respect to ergonomic assessment. Thus, the aim of this study was to find out the prevalence of WRMSDs in otolaryngologists in Mumbai and Navi Mumbai. A pre-validated, structured questionnaire was distributed to 150 otolaryngologists. Seventy-three otolaryngologists responded to the questionnaire. The questionnaire comprised of demographic and workload data, report of musculoskeletal symptoms and otolaryngologists' interpretation of casual and preventive factors of symptoms at workplace. Response rate of the survey was 48.6%. The total prevalence of WRMSDs in the otolaryngologists was 87.67%. Majority of those surveyed reported that they suffered from musculoskeletal problems which they attributed to the ergonomic flaws encountered during surgery (60.27%) and OPD (69.86%) respectively. Pain and discomfort during surgery experienced by the surgeons were most frequently attributed to the awkward and sustained postures adopted during surgery. Effective time management, ergonomically apt postures, intermittent change of posture, using back rest and availing skilled assistance during OPD and surgery, were the self-assessed corrective measures suggested by the respondents. The otolaryngologists' job profile puts them at high risk for WRMSDs.

Factors to Consider in Selecting Appropriate Computer Monitor Placement

Two studies were designed to explore visual and musculoskeletal strain associated with computer monitor placement. Effects of viewing angle, monitor size, keyboard familiarity, and task were studied in a lab setting. Outcome measures assessed visual and musculoskeletal strain, preference, and performance. To follow-up, participants in a field study were exposed to two of the placements tested in the lab. Preferences were split, but for most field subjects matched the placement associated with the least neck discomfort. Results of these studies and others suggest that, in consideration of individual differences and task requirements, the best solution may be providing users with a range of placement options and the ability and training to explore them.

Computer vision syndrome in presbyopia and beginning presbyopia: effects of spectacle lens type

PURPOSE

This office field study investigated the effects of different types of spectacle lenses habitually worn by computer users with presbyopia and in the beginning stages of presbyopia. Computer vision syndrome was assessed through reported complaints and ergonomic conditions.

METHODS

A questionnaire regarding the type of habitually worn near-vision lenses at the workplace, visual conditions and the levels of different types of complaints was administered to 175 participants aged 35 years and older (mean ± SD: 52.0 ± 6.7 years). Statistical factor analysis identified five specific aspects of the complaints. Workplace conditions were analysed based on photographs taken in typical working conditions.

RESULTS

In the subgroup of 25 users between the ages of 36 and 57 years (mean 44 ± 5 years), who wore distance-vision lenses and performed more demanding occupational tasks, the reported extents of 'ocular strain', 'musculoskeletal strain' and 'headache' increased with the daily duration of computer work and explained up to 44 per cent of the variance (rs = 0.66). In the other subgroups, this effect was smaller, while in the complete sample (n = 175), this correlation was approximately rs = 0.2. The subgroup of 85 general-purpose progressive lens users (mean age 54 years) adopted head inclinations that were approximately seven degrees more elevated than those of the subgroups with single vision lenses.

CONCLUSIONS

The present questionnaire was able to assess the complaints of computer users depending on the type of spectacle lenses worn. A missing near-vision addition among participants in the early stages of presbyopia was identified as a risk factor for complaints among those with longer daily durations of demanding computer work.

Human error identification for laparoscopic surgery: Development of a motion economy perspective

This study postulates that traditional human error identification techniques fail to consider motion economy principles and, accordingly, their applicability in operating theatres may be limited. This study addresses this gap in the literature with a dual aim. First, it identifies the principles of motion economy that suit the operative environment and second, it develops a new error mode taxonomy for human error identification techniques which recognises motion economy deficiencies affecting the performance of surgeons and predisposing them to errors. A total of 30 principles of motion economy were developed and categorised into five areas. A hierarchical task analysis was used to break down main tasks of a urological laparoscopic surgery (hand-assisted laparoscopic nephrectomy) to their elements and the new taxonomy was used to identify errors and their root causes resulting from violation of motion economy principles. The approach was prospectively tested in 12 observed laparoscopic surgeries performed by 5 experienced surgeons. A total of 86 errors were identified and linked to the motion economy deficiencies. Results indicate the developed methodology is promising. Our methodology allows error prevention in surgery and the developed set of motion economy principles could be useful for training surgeons on motion economy principles.

Association of affect with vertical position in L1 but not in L2 in unbalanced bilinguals

After judging the valence of the positive (e.g., happy) and the negative words (e.g., sad), the participants' response to the letter (q or p) was faster and slower, respectively, when the letter appeared at the upper end than at the lower end of the screen in Meier and Robinson's (2004) second experiment. To compare this metaphorical association of affect with vertical position in Chinese-English bilinguals' first language (L1) and second language (L2) (language), we conducted four experiments in an affective priming task. The targets were one set of positive or negative words (valence), which were shown vertically above or below the center of the screen (position). The primes, presented at the center of the screen, were affective words that were semantically related to the targets, affective words that were not semantically related to the targets, affective icon-pictures, and neutral strings in Experiment 1-4, respectively. In judging the targets' valence, the participants showed different patterns of interactions between language, valence, and position in reaction times across the experiments. We concluded that metaphorical association between affect and vertical position works in L1 but not in L2 for unbalanced bilinguals.

Monitor height ergonomics: A comparison of operating room video display terminals

A surgeon's eyes should be positioned 1 meter (m) distant and no more than 15° below the top of an operating monitor (0.27 m). We sought to determine which operating room video display terminal can best accommodate ergonomically optimized gaze during surgery. Floor to eye height was measured for surgeons in seated, perched, and standing positions. These ranges were then compared to vertical displacement ranges for monitors measured from floor to top of the screen. Eye height was measured for standing (1.56-1.80 m), perched (1.40-1.65 m), and seated (1.10-1.32 m) positions. The minimum distance (min) between the floor and the top of the monitor and the vertical mobility range (VR) of the monitor were measured throughout a tertiary medical center including towers with boom arms (TcB) (min: 1.58 m, VR: 0.37 m), towers without booms (TsB) (min: 1.82 m, VR: 0.025 m), ceiling mounted booms (CMB) (min: 1.34 m:, VR: 1.04 m), and portable monitors (PM) (min: 1.73 m, VR: 0.04 m). The tangent of 15° declination was used to calculate a correction factor to determine the minimum optimal ergonomic display height. The correction factor was subtracted from the eye height at each position to determine the lowest target height and the highest target floor to eye distance for each position. Analysis of variance with least significant difference post hoc testing identified all minimum distances and vertical ranges to be statistically different (p < 0.001). Monitor vertical displacement varied between styles of carts. CMB video display terminal systems can accommodate standing, perched and the tallest seated surgeons. TcB, TsB and PM systems cannot adequately accommodate all standing, perched or seated surgeons.

The vertical monitor position for presbyopic computer users with progressive lenses: how to reach clear vision and comfortable head posture

When presbyopic employees are wearing general-purpose progressive lenses, they have clear vision only with a lower gaze inclination to the computer monitor, given the head assumes a comfortable inclination. Therefore, in the present intervention field study the monitor position was lowered, also with the aim to reduce musculoskeletal symptoms. A comparison group comprised users of lenses that do not restrict the field of clear vision. The lower monitor positions led the participants to lower their head inclination, which was linearly associated with a significant reduction in musculoskeletal symptoms. However, for progressive lenses a lower head inclination means a lower zone of clear vision, so that clear vision of the complete monitor was not achieved, rather the monitor should have been placed even lower. The procedures of this study may be useful for optimising the individual monitor position depending on the comfortable head and gaze inclination and the vertical zone of clear vision of progressive lenses.

PRACTITIONER SUMMARY

For users of general-purpose progressive lenses, it is suggested that low monitor positions allow for clear vision at the monitor and for a physiologically favourable head inclination. Employees may improve their workplace using a flyer providing ergonomic-optometric information.

Touch displays: the effects of palm rejection technology on productivity, comfort, biomechanics and positioning

Direct touch displays can improve the human-computer experience and productivity; however, the higher hand locations may increase shoulder fatigue. Palm rejection (PR) technology may reduce shoulder loads by allowing the palms to rest on the display and increase productivity by registering the touched content and fingertips through the palms rather than shoulders. The effects of PR were evaluated by having participants perform touch tasks while posture and reaction force on the display were measured. Enabling PR, during which the subjects could place the palms on the display (but were not required to), resulted in increased wrist extension, force applied to the display and productivity, and less discomfort, but had no effect on the self-selected positioning of the display. Participants did not deliberately place their palms on the display; therefore, there was no reduction in shoulder load and the increased productivity was not due to improved hand registration. The increased productivity may have been due to reduced interruptions from palm contacts or reduced motor control demands.

Web-based office ergonomics intervention on work-related complaints: a field study

The aim of this study was a proof of concept to examine the effects of a Web-based office ergonomics intervention on subjects' individual workplace adjustments. An intervention study was conducted with 24 office workers lasting 6 weeks with three consecutive phases (before, 1 and 5 weeks after the intervention). Employees used a purpose-made website for adjusting their computer workplaces without any personal support of ergonomics experts. Workplace measurements were taken directly on site and by analysing photos taken of the employee. Self-reported complaints were assessed by filling in a questionnaire. It was found that 96% of the employees changed their workplaces on their own and retained them mostly unchanged after the intervention. Furthermore, self-reported musculoskeletal complaints and headache symptoms decreased significantly after the intervention. These findings suggest an improvement of workplace conditions so that cost-effective ergonomic Web-based interventions appear promising in further research and application.

Differences in children and adolescents' ability of reporting two CVS-related visual problems

The present study examined whether children and adolescents can correctly report dry eyes and blurred distance vision, two visual problems associated with computer vision syndrome. Participants are 913 children and adolescents aged 6-17. They were asked to report their visual problems, including dry eyes and blurred distance vision, and received an eye examination, including tear film break-up time (TFBUT) and visual acuity (VA). Inconsistency was found between participants' reports of dry eyes and TFBUT results among all 913 participants as well as for all of four subgroups. In contrast, consistency was found between participants' reports of blurred distance vision and VA results among 873 participants who had never worn glasses as well as for the four subgroups. It was concluded that children and adolescents are unable to report dry eyes correctly; however, they are able to report blurred distance vision correctly. Three practical implications of the findings were discussed.

PRACTITIONER SUMMARY

Little is known about children's ability to report their visual problems, an issue critical to diagnosis and treatment of children's computer vision syndrome. This study compared children's self-reports and clinic examination results and found children can correctly report blurred distance vision but not dry eyes.

Office ergonomics training and a sit-stand workstation: effects on musculoskeletal and visual symptoms and performance of office workers

Work Related Musculoskeletal Disorders (WMSDs) among office workers with intensive computer use is widespread and the prevalence of symptoms is growing. This randomized controlled trial investigated the effects of an office ergonomics training combined with a sit-stand workstation on musculoskeletal and visual discomfort, behaviors and performance. Participants performed a lab-based customer service job for 8 h per day, over 15 days and were assigned to: Ergonomics Trained (n = 11) or Minimally Trained (n = 11). The training consisted of: a 1.5-h interactive instruction, a sit/stand practice period, and ergonomic reminders. Ergonomics Trained participants experienced minimal musculoskeletal and visual discomfort across the 15 days, varied their postures, with significantly higher performance compared to the Minimally Trained group who had a significantly higher number of symptoms, suggesting that training plays a critical role. The ability to mitigate symptoms, change behaviors and enhance performance through training combined with a sit-stand workstation has implications for preventing discomforts in office workers.

Evaluation of the Factors which Contribute to the Ocular Complaints in Computer Users

CONTEXT

Use of information technology hardware given new heights to professional success rate and saves time but on the other hand its harmful effect has introduced an array of health related complaints causing hazards for our human health. Increased use of computers has led to an increase in the number of patients with ocular complaints which are being grouped together as computer vision syndrome (CVS). In view of that, this study was undertaken to find out the ocular complaints and the factors contributing to occurrence of such problems in computer users.

AIMS

To evaluate the factors contributing to Ocular complaints in computer users in Teerthanker Mahaveer University, Moradabad, U.P. India.

SETTINGS AND DESIGN

Community-based cross-sectional study of 150 subjects who work on computer for varying period of time in Teerthanker Mahaveer University, Moradabad, Uttar Pradesh.

MATERIALS AND METHODS

Two hundred computer operators working in different institutes offices and bank of were selected randomly in Teerthanker Mahaveer University, Moradabad, and Uttar Pradesh. 16 were non responders 18 did not come for assessment and 16 were excluded due to complaints prior to computer use making no response rate Twenty-one did not participate in the study, making the no response rate 25%. Rest of the subjects (n = 150) were asked to fill a pre-tested questionnaire, after obtaining their verbal consent Depending on the average hours of usage in a day, they were categorized into three categories viz. <2 hrs, 2-6 hrs, >6 hrs of usage. All the responders were asked to come to the Ophthalmic OPD for further interview and assessment.

STATISTICAL ANALYSIS USED

Simple proportions and Chi-square test.

RESULTS

Among the 150 subjects studied major ocular complaint reported in descending order were eyestrain. (53%). Occurrence of eye strain, ( 53.8%), itching ( 47.6%) and burning (66.7%) in subjects using computer for more than 6 hours. distance from computer screen with respect to eyes, use of antiglare screen, taking frequent breaks, use of LCD monitor and adjustment of brightness of monitor screen bear a significant association with these ocular complaints in computer users.

CONCLUSIONS

Eye strain is the most common ocular complaints among computer users working for more than 6 hours a day. We also found that maintaining ideal distance from screen, keeping level of eyes above the top of screen, taking frequent breaks, using LCD monitors and using antiglare screen and adjusting brightness levels according to workplace reduced these ocular complaints to a significant level.

Ergonomic factors on task performance in laparoscopic surgery training

This paper evaluates the effect of ergonomic factors on task performance and trainee posture during laparoscopic surgery training. Twenty subjects without laparoscopic experience were allotted into 2 groups. Group 1 was trained under the optimal ergonomic simulation setting according to current ergonomic guidelines (Condition A). Group 2 was trained under non-optimal ergonomic simulation setting that can often be observed during training in a skills lab (Condition B). Posture analysis showed that the subjects held a much more neutral posture under Condition A than under Condition B (p<0.001). The subjects had less joint excursion and experienced less discomfort in their neck, shoulders, and arms under Condition A. Significant difference in task performance between Conditions A and B (p<0.05) was found. This study shows that the optimal ergonomic simulation setting leads to better task performance. In addition, no significant differences of task performance, for Groups 1 and 2 using the same test setting were found. However, better performance was observed for Group 1. It can be concluded that the optimal and non-optimal training setting have different learning effects on trainees' skill learning.

A field intervention examining the impact of an office ergonomics training and a highly adjustable chair on visual symptoms in a public sector organization

OBJECTIVE

Examine the effect of a multi-component office ergonomics intervention on visual symptom reductions.

METHODS

Office workers were assigned to either a group receiving a highly adjustable chair with office ergonomics training (CWT), a training-only group (TO) or a control group (C). A work environment and health questionnaire was administered 2 and 1 month(s) pre-intervention and 3, 6, and 12 months post-intervention. Multi-level statistical models tested hypotheses.

RESULTS

The CWT intervention lowered daily visual symptoms (p < 0.01) post-intervention. The TO group did not significantly differ from the control group. The CWT group differed significantly from the TO group (p = 0.01) post-intervention.

CONCLUSION

Workers who received a highly adjustable chair and office ergonomics training had reduced visual symptoms and the effect was maintained through twelve months post-intervention. The lack of a training-only group effect supports implementing training in conjunction with the highly adjustable chair to reduce visual symptoms.

User discomfort, work posture and muscle activity while using a touchscreen in a desktop PC setting

An experimental study was conducted to evaluate physical risk factors associated with the use of touchscreen in a desktop personal computer (PC) setting. Subjective rating of visual/body discomfort, shoulder and neck muscle activity, elbow movement and user-preferred positions of the workstation were quantified from 24 participants during a standardised computer use task with a standard keyboard and a mouse (traditional setting), with a touchscreen and the standard keyboard (mixed-use condition) and with the touchscreen only. The use of a touchscreen was associated with a significant increase of subjective discomfort on the shoulder, neck and fingers, myoelectric activity of shoulder and neck muscles and percentage of task duration that arms were in the air. Participants placed the touchscreen closer and lower when using touch interfaces compared with the traditional setting. Results suggest that users would need more frequent breaks and proper armrests to reduce physical risks associated with the use of a touchscreen in desktop PC settings. Statement of Relevance: In this study, subjective discomfort, work posture and muscle activity of touchscreen desktop PC users were quantitatively evaluated. The findings of this study can be used to understand potential risks from the use of a touchscreen desktop PC and to suggest design recommendations for computer workstations with the touchscreen.

Dyslexic children are confronted with unstable binocular fixation while reading

Reading requires three-dimensional motor control: saccades bring the eyes from left to right, fixating word after word; and oblique saccades bring the eyes to the next line of the text. The angle of vergence of the two optic axes should be adjusted to the depth of the book or screen and - most importantly - should be maintained in a sustained manner during saccades and fixations. Maintenance of vergence is important as it is a prerequisite for a single clear image of each word to be projected onto the fovea of the eyes. Deficits in the binocular control of saccades and of vergence in dyslexics have been reported previously but only for tasks using single targets. This study examines saccades and vergence control during real text reading. Thirteen dyslexic and seven non-dyslexic children read the French text “L'Allouette” in two viewing distances (40 cm vs. 100 cm), while binocular eye movements were measured with the Chronos Eye-tracking system. We found that the binocular yoking of reading saccades was poor in dyslexic children (relative to non-dyslexics) resulting in vergence errors; their disconjugate drift during fixations was not correlated with the disconjugacy during their saccades, causing considerable variability of vergence angle from fixation to fixation. Due to such poor oculomotor adjustments during reading, the overall fixation disparity was larger for dyslexic children, putting larger demand on their sensory fusion processes. Moreover, for dyslexics the standard deviation of fixation disparity was larger particularly when reading at near distance. We conclude that besides documented phoneme processing disorders, visual/ocular motor imperfections may exist in dyslexics that lead to fixation instability and thus, to instability of the letters or words during reading; such instability may perturb fusional processes and might – in part - complicate letter/word identification.

User-preferred position of computer displays: effects of display size

OBJECTIVE

Effects of display size and dual display setting on preferred display and keyboard positions were evaluated.

BACKGROUND

User-preferred display position may vary as its size changes or when multiple displays are used. It is also not known whether the use of larger displays or multiple displays would influence positioning of the keyboard.

METHOD

Participants (N=19) who had normal visual acuity (20/30 or better) determined preferred positions of the display and the keyboard during a data entry task in four display setups (19, 24, 27.5, and dual 19 in.). The size of capital characters (3.2 mm high) was kept consistent between setups.

RESULTS

Preferred viewing distance ranged from 0.68 m (19-in. display) to 0.76 m (27.5-in. display). No significant differences in viewing distance and display height were found between the single 19-in. display and dual 19-in. displays setups. The preferred position of the keyboard was consistent between display setups.

CONCLUSION

Participants placed larger displays farther and lower while maintaining the display top at or near eye height. Preferred position of the dual displays in landscape setting did not differ from that of a single display. It appears that the preferred display position varies with the vertical dimension of the overall viewable area of the display.

APPLICATION

The results of this study can be used to determine the dimensions or adjustability of computer workstations for larger displays or multiple displays settings.

Evidence-based guidelines for the wise use of computers by children: physical development guidelines

Computer use by children is common and there is concern over the potential impact of this exposure on child physical development. Recently principles for child-specific evidence-based guidelines for wise use of computers have been published and these included one concerning the facilitation of appropriate physical development. This paper reviews the evidence and presents detailed guidelines for this principle. The guidelines include encouraging a mix of sedentary and whole body movement tasks, encouraging reasonable postures during computing tasks through workstation, chair, desk, display and input device selection and adjustment and special issues regarding notebook computer use and carriage, computing skills and responding to discomfort. The evidence limitations highlight opportunities for future research. The guidelines themselves can inform parents and teachers, equipment designers and suppliers and form the basis of content for teaching children the wise use of computers. STATEMENT OF RELEVANCE: Many children use computers and computer-use habits formed in childhood may track into adulthood. Therefore child-computer interaction needs to be carefully managed. These guidelines inform those responsible for children to assist in the wise use of computers.

The eye-complaint questionnaire in a visual display unit work environment: internal consistency and test-retest reliability

The internal consistency and test-retest reliability of a 10-item eye-complaint questionnaire (ECQ) were examined within a sample of office workers. Repeated within-subjects measures were performed within a single day and over intervals of 1 and 7 d. Questionnaires were completed by 96 workers (70% female, mean age 36.4 years) who perform more than 4 h of visual display unit work each day. The internal consistency of the ECQ was high (alpha = 0.801). Although test-retest reliability was low within a single day (morning and afternoon) (intra-class correlation coefficient (ICC) = 0.68, 95% CI 0.38, 0.82), it was good between two morning measurements over a 1-d interval (ICC = 0.91 95% CI 0.87, 0.94) and between morning measurements with a 7-d interval (ICC = 0.87, 95% CI 0.81, 0.92). The ICC between afternoon measurements over a 1-week interval was moderate (ICC = 0.78, 95% CI 0.66, 0.85). This questionnaire is a reliable and consistent instrument for easily assessing eye complaints in office work. The timing of the measurements must be kept in consideration since measurements are confounded by exposures over the day.