The Impact of Lenses on Musculoskeletal and Visual Complaints in VDU Workers With Neck Complaints
Condition: Neck Pain
MeSH terms: Neck Pain
Study type: Interventional

Summary: 
      The aim of this study is to investigate the impact of wearing visual display units (VDU)
      lenses versus progressive lenses on musculoskeletal and visual complaints in VDU workers with
      work related neck complaints. This will be evaluated by means of questionnaires (Neck
      Disability Index and Visual Fatigue Questionnaire), muscle tone, elasticity and stiffness,
      pressure pain threshold and 2D video analysis of head posture during a VDU task.
    

Detailed description: 
      The use of visual display units (VDU) is often accompanied by physical complaints of the
      neck, shoulder, forearm and hand, especially in people who make extensive use of computers at
      work. Besides this, VDU operators also experience eye discomfort and vision problems when
      working with the computer for a long period.

      With the increase of computer use, VDU glasses were developed. They provide a clear vision of
      the intermediate zone at a distance of approximately 70 centimeters, which is closer than
      distant vision at a distance of more than 2 meters (e.g. driving), but further than near
      vision at a distance of 40 centimeters (e.g. reading), so the computer screen is seen clear
      without the need for excessive focusing effort or bad postures. Progressive lenses have some
      lens power for this intermediate zone as well, but this zone might not be large enough for
      comfortable and ergonomic computer work. VDU glasses are often progressive glasses as well,
      so they can be used to read and see things beyond the computer screen clear during computer
      work.

      The research question of this study is "What is the impact of wearing progressive VDU lenses
      versus progressive lenses, for six months, on both musculoskeletal and visual complaints in
      VDU workers with work related neck complaints ?"

      To find an answer to this question, 40 VDU workers (men and women) with work related
      neck/shoulder complaints, were recruited from a bank office where they perform predominantly
      VDU work. All participants will receive information and have to sign an informed consent
      form.

      A questionnaire concerning visual and musculoskeletal complaints, in which the Neck
      Disability Index (NDI) Questionnaire had to be completed at the beginning of the experiment.
      Participants were tested with their old glasses in a landscape office while performing a 20
      minute VDU task. Before and after the task, viscoelastic properties (MyotonPRO®) of the
      trapezius muscle and the PPT (WagnerTM FDX 50 hand-held pressure algometer) of the trapezius
      muscle, the levator scapulae muscle and the infraspinatus muscle were measured. A 2D video
      analysis was performed during the task.The Forward Head Angle (FHA) and the Forward Shoulder
      Angle (FSA) was measured afterwards. After this, participants were asked to fill out a short
      questionnaire, in which the Visual Fatigue Questionnaire was included, every two weeks during
      two months. On the 15th of June, 2015 the participants received new glasses and were asked to
      wear these for six months during computer work. During this period the same short
      questionnaire had to be filled out every two weeks. The test procedure will be repeated with
      the new glasses after six months of wearing these. A shorter version of the first
      questionnaire will be completed at the end of the experiment.
    

Intervention name(s): VDU lenses (Zeiss® Officelens Plus); Progressive lenses (Zeiss® Multifocal Precision Plus)
Intervention type(s): Other; Other
Intervention description(s): The treatment group (n=22) was given progressive VDU glasses (Zeiss® Officelens Plus), specially designed for VDU work. The participants were asked to wear their new glasses for six months during computer work.; The comparison group (n=18) was given progressive glasses (Zeiss® Multifocal Precision Plus). The participants were asked to wear their new glasses for six months during computer work.
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Investigator)
Primary purpose: Other
Keywords: VDU workers; VDU lenses; Neck complaints; Visual complaints