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A prospective epidemiological field study covering a 2 years period has earlier been published. The study has a parallel group design with two intervention groups (T and S) and one control group (C) of Visual Display Unit (VDU) operators. The present paper covers the period from 2 to 6 years of the study. After 3.5 years, the C group got the same intervention in terms of new lighting system, new workplaces and at last an optometric examination and corrections if needed. The C group reported a significant reduction in visual discomfort after interventions while the two groups (T and S) continued to report significant reduction of visual discomfort after 6 years. By supporting the forearm on the table top, the C group reported significant reduction of shoulder and neck pain while the T group reported significant reduction in shoulder and back pain after 6 years. Organizational and psychosocial factors at work and outside work did not show any significant changes during the study period. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

This study investigated the effect of moving from single occupancy offices to a landscape environment. Thirty-four Visual Display Unit (VDU) operators reported significantly worsened condition of lighting and glare in addition to increased visual discomfort. For visual discomfort, the difference with 95% confidence interval was 10.7 (1.9-19.5) Visual Analog Scale (VAS) as group mean value. The most reasonable explanation for these results may be that the operators were glared from high luminance from the windows, when the Venetian blinds were not properly used. Glare was significantly correlated with visual discomfort, rs=0.35. Both illuminance and luminance in the work area, and contrast reduction on the VDU screen were in line with recommendations from CIE for VDU work. In a regression analysis, the visual discomfort explained 53% of the variance in the neck and shoulder pain. In the office landscape, the eye blink rate during habitual VDU work was recorded for 12 randomly selected operators from the 34 participants. A marked drop in eye blink rate during VDU work was found when this was compared to "easy conversation" (VDU work, mean=9.7 blinks per minute; "easy conversation," mean=21.4 blinks per minute). Participants reported many of the organizational and psychosocial conditions and work factors worse when landscape office was compared to single occupancy office. These factors may have influenced the musculoskeletal pain. However, the pain level was still low at 6 years and not significantly different when compared with the start of the study period, except for a small but significant increase in shoulder pain. In this study, visual discomfort is clearly associated with pain in the neck and shoulder area.

In an initial study, 18 VDT operators were found to have a higher muscle load in the neck/ shoulder region when using progressive lenses compared with single-vision lenses, while working on a VDT unit. For single-vision lenses, a higher flexion angle in the neck was also discovered. The present study investigates whether this higher muscle load is reduced when a progressive correction is worn for a three-month period. Adaptation in terms of reduced muscle load measured by electromyography (EMG) was not discovered. Head flexion angle was smaller when using progressive correction as compared with single-vision lenses. Some practical implications for occupational optometry are discussed.