<qa>  What was the NDI Questionnaire?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. 