Hillevi Hemphälä

A visual ergonomics intervention in mail sorting facilities : Effects on eyes, muscles and productivity

Visual requirements are high when sorting mail. The purpose of this visual ergonomics intervention study was to evaluate the visual environment in mail sorting facilities and to explore opportunities for improving the work situation by reducing visual strain, improving the visual work environment and reducing mail sorting time. Twenty-seven postmen/women participated in a pre-intervention study, which included questionnaires on their experiences of light, visual ergonomics, health, and musculoskeletal symptoms. Measurements of lighting conditions and productivity were also performed along with eye examinations of the postmen/women. The results from the pre-intervention study showed that the postmen/women who suffered from eyestrain had a higher prevalence of musculoskeletal disorders (MSD) and sorted slower, than those without eyestrain. Illuminance and illuminance uniformity improved as a result of the intervention. The two post-intervention follow-ups showed a higher prevalence of MSD among the postmen/women with eyestrain than among those without. The previous differences in sorting time for employees with and without eyestrain disappeared. After the intervention, the postmen/women felt better in general, experienced less work induced stress, and considered that the total general lighting had improved. The most pronounced decreases in eyestrain, MSD, and mail sorting time were seen among the younger participants of the group.

Vision ergonomics at recycling centres.

All municipalities in Sweden offer their inhabitants a service for disposing of large-size and hazardous waste at local recycling centres. Opening hours at these centres include hours of darkness. The aims of this study were to 1) describe user and employee experiences of lighting and signs at Swedish recycling centres, 2) measure and assess the lighting system at the two recently built recycling centres in Linköping and to assess the legibility and visibility of the signs used and 3) propose recommendations regarding lighting and signs for recycling centres. Interviews and questionnaires were used to assess experiences of employees and users, and light measurements were performed. By observing users, activities with different visual demands at different areas within the recycling centres were identified. Based on the literature, standards and stakeholder experiences, recommendations regarding lighting systems and sign design, illuminance, luminance and uniformity are proposed for recycling centres.

Visual ergonomics interventions in mail sorting facilities

This study was performed between 2004 and 2011 at mail sorting facilities in Sweden. During this time, different interventions were performed. The first was a lighting intervention that had a positive impact on the postal workers, especially those with eyestrain. A new lighting system also improved the illuminance and gave better light distribution. The second intervention involved new personal spectacles for the postal workers who needed them and this had a positive effect on eyestrain. The third intervention involved a specific type of sorting spectacles for the postal workers who already used progressive lenses privately. The reading distances that the postal workers had while sorting the mail was inverted to the distances in their regular progressive lenses. The new sorting spectacles had a positive effect on head postures and on muscular activity.

Optimal correction in spectacles - intervention effects on eyestrain and musculoskeletal discomfort among postal workers.

BACKGROUND The static posture of postal workers when sorting mail can lead to musculoskeletal discomfort. Research has shown a connection between eyestrain and upper-body musculoskeletal discomfort in general, including postal workers. A previous study of postal workers found that most of those with eye strain were in need of a new correction in their existing spectacles. OBJECTIVE Evaluate intervention effects on eyestrain and musculoskeletal discomfort with new spectacles for postal workers. METHODS Postal workers subjectively reported eyestrain, musculoskeletal discomfort and their opinions of the visual environment via questionnaires pre- and post-intervention. After an eye examination the postal workers were divided into two groups: those who needed new spectacles and those who did not. RESULTS Those who needed new spectacles showed a higher prevalence of eyestrain and musculoskeletal discomfort pre-intervention. Post-intervention, the postal workers rated their vision better and the average eyestrain and musculoskeletal discomfort decreased for both groups. These workers also experienced a decrease in discomfort on the left (static) side of the neck while sorting mail. CONCLUSION An intervention providing the optimal correction reduces eyestrain and decreases musculoskeletal discomfort, especially from the neck.

Conceptual and Practical Strategy Work to Promote Ergonomics/Human Factors in Sweden

This paper describes the results of the conceptual and practical strategy work performed by the Swedish Ergonomics and Human Factors Society (EHSS) today. The rationale of EHSS is to strengthen the quality of ergonomics/human factors knowledge and practice in Sweden and form a multidisciplinary platform across disciplines and professions for collaboration and for knowledge sharing. EHSS gathers about 350 members, representing different occupations in industry, academia and the public sector. Together, EHSS members hold knowledge and experience in physical, cognitive and organizational ergonomics and its application in working life and society. The overall aim of this paper is to inspire related societies and stakeholders to initiate discussions about strategies and future projects that allow for collaboration and knowledge sharing. Proposedly follow the EHSS model where we have formed a multidisciplinary platform for collaboration across disciplines and professions. The activities initiated and supported by EHSS are one step towards broadening the knowledge and application of HFE in Sweden, and to comprise new arenas of specialization. By participating in the key areas in society such as teaching, standardization, product development and occupational safety and health, the work of EHSS is one piece of the puzzle to improve human activities in the future. The vision is that together, we can improve safety, efficiency and well-being for all.

Lighting at computer workstations.

BACKGROUND The visual conditions for computer work are complex and include several factors that need to be well controlled. These factors include the lighting system, the design of the computer and screen itself, the screens position and orientation within the room, the surface reflectances and colours of the room, and the visualability of the worker. OBJECTIVE The objective was to review the literature (including standards) on lighting for computer work in an accessible summary. This contribution focuses on lighting for computer work, but the reader is reminded of the fact that lighting continuously interacts with the other factors mentioned above. RESULTS/CONCLUSION The combined visual conditions shall enable the worker to see and perform the work task without causing unnecessary strain for the eyes or the other parts of the body. The main lighting-related factors in the visual environment to evaluate are: illuminance, luminance, direction of light, glare, correlated colour temperature of the light source (CCT), colour rendering of the light source, and the non-visual effects (such as non-visual flicker). A visual ergonomics checklist is presented as a guide to analyse the visual environment.

Working spectacles for sorting mail.

BACKGROUND Sorting mail into racks for postmen is visually demanding work. This can result in backward inclination of their heads, especially more pronounced for those who use progressive addition lenses. OBJECTIVE To evaluate the effects of customized working spectacles on the physical workload of postmen. METHODS Twelve male postmen sorted mail on two occasions: once using their private progressive spectacles and once using customized sorting spectacles with inverted progressive lenses. Postures and movements of the head, upper back, neck, and upper arms were measured by inclinometry. The muscular load of the trapezius was measured by surface electromyography. RESULTS With the customized sorting spectacles, both the backward inclination of the head and backward flexion of the neck were reduced (3°), as well as the muscular load of the right upper trapezius, compared to sorting with private spectacles. However, with the sorting spectacles, there was a tendency for increased neck forward flexion, and increased sorting time. CONCLUSION The reduction in work load may reduce the risk for developing work-related musculoskeletal disorders due to the positive reduction of the backward inclination of the head. But the tendency for increased neck forward flexion may reduce the positive effects. However, the magnitude of the possible reduction is difficult to predict, especially since quantitative data on exposure-response relationships are unknown. Alternative working spectacles with inverted near progressive lenses ought to be evaluated. They should still result in a positive reduced backward inclination of the head and may not cause any increased forward flexion.