Possible Effects from Using DSE  Postural Problems Upper limb pains and discomfort

175 several categories of ergonomic risks and provide a good illustration of the need to tackle ergonomic issues in a holistic manner.

18.5.1 Possible Effects from Using DSE  Postural Problems Upper limb pains and discomfort

These range from fatigue or soreness in the arm, hand and shoulder areas to chronic soft tissue disorders like carpal tunnel syndrome - inflammation of the sheath surrounding the tendons that flex the fingers. The contribution of individual risk factors e.g. keying rates to the onset of any disorder is not clear. It is likely that a combination of factors are involved. Prolonged static posture of the back, neck and head are known to cause musculoskeletal problems. Awkward positioning of the hands and wrists, for example as result of poor work technique or inappropriate work height, are other likely factors. Outbreaks of soft tissue disorders among keyboard operators have often been associated with high workloads, combined with tight deadlines. This variety of factors contributing to display screen work risk requires a risk reduction strategy that embraces proper equipment, furniture, training, job design and work planning.  Visual Problems Eye and eyesight effects Like other visually demanding tasks, DSE work does not cause eye damage, nor does it make existing defects worse. It may, however, make users with pre-existing vision defects more aware of them and some users, may experience temporary visual fatigue, leading to a range of symptoms, such as impaired visual performance, red or sore eyes, headaches, or behavioural changes for example, postural change. These symptoms may be caused by staying in the same position and concentrating for a long time, by poor positioning of the display screen equipment, by poor legibility of the screen or source documents, by poor lighting conditions, including the presence of glare and reflections, andor by a drifting, flickering or jittering image on the screen. 176 Uncorrected vision defects can make work with a display screen more tiring or stressful than would otherwise be the case.  Fatigue and Stress Many symptoms described by display screen users reflect stresses arising from the users task. They may be secondary to upper limb or visual problems but they are more likely to be caused by poor job design or work organisation, lack of control of the work by the user, under-utilisation of skills, high-speed repetitive working or social isolation.

18.6 Making an Assessment  Identification of DSE Users