The purpose of the present study was to extend the knowledge offunctional linkages between visual and mental load, performance, and prefrontalcortex (PFC) activity, during forestry forwarding work. Eleven healthy participants,range 21–51 years old, with a minimum of 1-year work experience,carried out the task of loading logs along a standardized path in a machinesimulator during two counterbalanced test conditions: (i) conventional cranecontrol, and; (ii) semi-automated crane control. Mental load was assessed byquantification of oxygenated hemoglobin (HbO2) concentration changes overthe right dorsolateral prefrontal cortex (dlPFC) via non-invasive functional nearinfrared spectrometry (fNIRS). Visual, autonomic, and motoric control variableswere measured and analyzed in parallel along with the individual level of performance.Linear Mixed Models (LMM) analysis indicated more mental loadduring conventional crane work. Collectively, our data suggest that fNIRS is aviable tool which can be used in neuroergonomic research to evaluate physiologicalactivity levels in PFC.

The present study aimed to identify whether or not an increase in ciliary-muscle contraction force, when the eye-lens is adjusted for viewing at a near distance, result in an increase in trapezius muscle activity, while performing a natural work task. Twelve participants, ranging in age from 21 to 32 years, performed a computer-mouse work task during free gaze conditions. A moving visual target was tracked with a computer mouse on a screen placed at two different distances from the eyes, 25 cm and 50 cm. Tracking performance, eye accommodation, and bilateral trapezius muscle activity were measured continuously. Ciliary-muscle contraction force was computed according to a formula which takes into account the age-dependent, non-linear relationship between contraction force of the ciliary muscle and the produced level of eye accommodation. Generalized Estimating Equations analyses were performed. On the dominant hand side and for the nearest screen distance, there was a significant effect of ciliary-muscle contraction force on the trapezius muscle activity (p<0.001). No other effects were significant (p>0.05). The results support the hypothesis that high visual demands, during computer mouse work, increase ciliary muscle contraction force and contribute to a raise of the sustained level of trapezius muscle activity. The current study specifically clarifies the validity of the relationship between ciliary-muscle contraction force and trapezius muscle activity and demonstrates that this relationship is not due to a general personal trait. We conclude that a high level of ciliary muscle contraction force can contribute to a development of musculoskeletal complaints in the neck-shoulder area.

Genom att synens betydelse försummas är risken stor att barn inte får rätt hjälp, skriver optikern Fredrik Hägnefelt och forskarna Hans Richter och Rune Brautaset.

Mobile technology has revolutionised how we work. It is now relatively easy to work anywhere and anytime, but this has placed the onus on mobile (or flexible) workers to set up their own work environment for comfort and ease of use. Vision is an important driver of posture, and hence visual ergonomics principles are integral for setting up digital devices. If mobile workers do not have visual ergonomics knowledge, or are unable to apply visual ergonomics knowledge to appropriately set up their work environment, then they are at risk of developing visual-related occupational health issues due to exposure to adverse physical work environments.

To address this potential health care issue, we propose the introduction of Visual Ergonomics Health Literacy. This would provide mobile workers (including school children) with the knowledge and skills to set up their work environment for comfort and ease of use, wherever they work. It is important to address this issue now before we have a widespread epidemic of discomfort and injury from not applying sound visual ergonomics principles to work environments.

BACKGROUND:

Visual impairment is globally among the most prevalent disabilities. Research concerning the health consequences of visual deficits is challenged by confounding effects of age, because visual impairment becomes more prevalent with age. This study investigates the influence of visual deficits on visual, musculoskeletal and balance symptoms in adults with and without visual impairment, while controlling for age effects.

METHODS:

Thirty-nine patients with visual impairment, aged 18-72 years, were compared to 37 age-matched controls with normal vision, allocated to two age groups: < 45 and ≥ 45 years. Self-reported symptoms were measured using the Visual, Musculoskeletal and Balance Symptoms Questionnaire and compared with demographic and optometric variables.

RESULTS:

In total, patients with visual impairment reported more symptoms than age-matched normally sighted controls. Younger adults in the control group were almost free from symptoms, whereas younger adults with visual impairment reported levels of symptoms equal to older adults with visual impairment. Multiple logistic regression modelling identified use of eyeglasses, magnifying aids and presence of anisometropia to be the most influential risk factors for reporting visual, musculoskeletal and balance symptoms, with accentuated influence on balance symptoms.

CONCLUSIONS:

People with visual impairments and people with age-related normal visual deficits are both predisposed to report visual, musculoskeletal and balance symptoms relative to people without visual defects or need for eye-wear correction. Age-related variations in symptoms were observed in the control groups but not in the visual impairment groups, with younger visual impairment patients reporting as many symptoms as older visual impairment patients. These findings indicate a need for a wider interdisciplinary perspective on eye care concerning people with visual impairment and people with need for habitual daily use of eye wear correction.

Introduction: The main purpose of this cross-sectional study was to investigate whether visual well-being and health act as a mediating factor between perceived visual ergonomic working conditions and self-rated visual performance among office workers who perform administrative tasks and computer-based work at the Swedish Tax Agency.

Methods: A questionnaire was sent to 94 office workers addressing: 1) perceived visual quality of the visual display units; 2) prevalence of eye symptoms; and 3) self-rated visual performance. Eighty-six persons (54 women (63 %), 31 men (36 %), and 1 of unspecified sex) answered the questionnaire. Multiple regression analysis investigated the association between visual ergonomic working conditions and visual performance, with and without visual well-being and health as a mediator.

Results: The group mean of the Indexed survey questions indicated reasonably good quality visual ergonomic working conditions, a relative absence of eye symptoms, and acceptable self-rated visual performance. Results from multiple regression analysis showed a significant association between perceived visual ergonomic working conditions and self-rated visual performance (r² = 0.30, β = 0.327, p < 0.01). When visual well-being and health was used as a mediator, the association between perceived visual ergonomic working conditions and self-rated visual performance remained the same (r² = 0.32, β = 0.315, p < 0.01).

Discussion: It was surprising to discover that self-rated visual performance  was independent of visual health and well-being. Possible explanations include exposure factors not included in the current study, such as dry air and sensory irritation in eyes, psychosocial stress, time spent performing near work activities or time exposed to visually deficient working conditions. The strong connection between satisfaction with visual ergonomics work conditions and productivity found in this study has implications for workplace profitability and staff satisfaction. If productivity of office workers is improved by better visual ergonomics work conditions, then managers within workplaces may be able to improve work outcomes by optimizing the physical work environment.

This study is concerned with a new method for partly automating forestry harvesting work. Work-related injuries and constant demands for a higher productivity are two of the many arguments for why forestry work must be improved. Forestry work places great mental demands on the driver because they must continuously evaluate and act on relevant parts in a heavy visual information flow. Against this background the purpose of the present study was to extend the knowledge of functional linkages between visual and mental fatigue, performance, and prefrontal cortex activity, during semi-automated and conventional forestry harvesting work. Eleven healthy participants, range 21–51 years old, with a minimum of 1-year work experience, carried out the task of loading logs along a standardized path in a machine simulator during two counterbalanced 45-min periods: (i) conventional forest harvesting, and; (ii) semi-automated forest harvesting. Equal emphasizes was put on accuracy and speed. During manual forest harvesting the driver controlled the crane arm, used to load logs into the load space of the forest vehicle (“forwarder”), by manually operating the joysticks and so guide the crane to the location of the log and then back to the load space. During semi-automatic forest harvesting the driver moved the crane with the press of a button to a pre-programmed location near the log and then, after another button press, to a pre-programmed location within the load space. The following joystick usage parameters were considered for the statistical analysis: Sequential work cycle number, work phase (1-loading in basket, 2-movement to log, 3-picking up log, 4-movement to load space), number of simultaneously used controls across samples of one phase, number of direction changes of joystick movements per phase. Mental load was assessed by quantification of oxygenated hemoglobin (HbO₂) concentration changes over the right dorsolateral prefrontal cortex (dlPFC) via non-invasive functional near infrared spectrometry (fFNIRS: PortaLite mini, Artinis Medical Systems, Zetten, the Netherlands). The frequency and duration of horizontal amplitudes of eye/head/neck angles was assessed continuously with 8 SmartEye cameras and used as a measure of visual load. NASA-TLX and Borg CRS was used to assess perceived mental and physical fatigue. Linear Mixed Model will be used to test and to analyze the effect of the duration of work, joystick usage, work type (manual or semi-automated) and perceived mental and physical effort on the outcome of oxygenated hemoglobin concentration. This study contributes with new knowledge of the consequences of the current increase in automation. The 4^th industrial revolution can have tremendous implications on how we perceive and organize work in the future, but little is still known about the impact on human body and brain.