This study appears to be one of few intervention studies with focus on eyestrain and lighting on non-computer workplaces. Previous studies have shown strong connections between eyestrain and musculoskeletal strain. The eyes “lead the body” and if the picture on the retina is unfocused the body adjusts the posture, trying to improve the image through changing the viewing distance. This can lead to an unnatural body posture which can contribute in the development of musculoskeletal disorders. A good visual environment with proper illuminance, good luminance contrast relationship, good uniformity value of the illuminance and no glare are the best conditions in order to function well at a visually demanding work. Sorting mail is a task that needs good visual ergonomics and can therefore be improved by a change in the visual environment. The overall purpose of this thesis is to investigate if a good visual environment have an impact on eyestrain, musculoskeletal strain, productivity, wellbeing, and work induced stress. This thesis is based on a literature review and a lighting intervention, with one part before the intervention and two follow-up parts, summer and winter. The results are based on objectively measurements; lighting, time studies, and optometric eye examinations, and two questionnaires. The first questionnaire concerned visual ergonomics and the second had a focus on wellbeing and experience of work related tasks. The postmen experienced the new lighting and labeling as improvement. A small decrease in the amount of eyestrain was present, and the younger postmen had a decrease of the musculoskeletal strain. The postmen with eyestrain got a small improvement of the sorting time. When the lighting was improved another factor that could cause strain appeared, the need for good correction in their glasses was identified as the main remaining factor that could cause the observed strain. / Report code: LiU-Tek-Lic-2008:8.

<p>This study appears to be one of few intervention studies with focus on eyestrain and lighting on non-computer workplaces. Previous studies have shown strong connections between eyestrain and musculoskeletal strain. The eyes “lead the body” and if the picture on the retina is unfocused the body adjusts the posture, trying to improve the image through changing the viewing distance. This can lead to an unnatural body posture which can contribute in the development of musculoskeletal disorders.</p><p>A good visual environment with proper illuminance, good luminance contrast relationship, good uniformity value of the illuminance and no glare are the best conditions in order to function well at a visually demanding work. Sorting mail is a task that needs good visual ergonomics and can therefore be improved by a change in the visual environment.</p><p>The overall purpose of this thesis is to investigate if a good visual environment have an impact on eyestrain, musculoskeletal strain, productivity, wellbeing, and work induced stress.</p><p>This thesis is based on a literature review and a lighting intervention, with one part before the intervention and two follow-up parts, summer and winter. The results are based on objectively measurements; lighting, time studies, and optometric eye examinations, and two questionnaires. The first questionnaire concerned visual ergonomics and the second had a focus on wellbeing and experience of work related tasks.</p><p>The postmen experienced the new lighting and labeling as improvement. A small decrease in the amount of eyestrain was present, and the younger postmen had a decrease of the musculoskeletal strain. The postmen with eyestrain got a small improvement of the sorting time. When the lighting was improved another factor that could cause strain appeared, the need for good correction in their glasses was identified as the main remaining factor that could cause the observed strain.</p> / Report code: LiU-Tek-Lic-2008:8.