Musculoskeletal, visual and psychosocial stress in VDU operators before and after multidisciplinary ergonomic interventions.

The study has a parallel group design with two intervention groups (T and S) and one control group (C) of VDU operators. Three serial interventions were carried out in the T and S groups, first a new lighting system, then new workplaces and last an optometric examination and corrections if needed. The new lighting gave significantly increased illuminance levels, increased luminances of the room surfaces and better luminance distribution. The two intervention groups reported significant improvement of the lighting conditions, as well as of the visual conditions and significantly reduced visual discomfort and glare. Significant reduction of headache was found in one of the intervention groups. Optometric corrections reduced the visual discomfort in both the intervention groups. When looking at those given new corrections, a significant reduction was found in the T group and a clear tendency was also found in the S group. The C group reported no improvements for any of these health outcomes. The workplace intervention gave the operator the possibility to support the whole forearm and hand on the table top. Before the intervention there were no significant differences between the three groups regarding shoulder pain and static trapezius electromyographic (EMG) load. Two years after the intervention, a significant reduction of shoulder pain was reported in the T and S groups in parallel with a significant reduction in static trapezius load, while no such reduction was found in the C group. At the same time, both static trapezius load and shoulder pain were significantly lower in the T and S groups compared with the C group. Pain in the forearm and hand showed no significant changes in any of the groups during the study period. However, there seem to be a relationship between pain in the forearm and hand and the time the operator used the mouse. The C group reported significantly higher intensity of pain and used the mouse significantly more than the S group.