VDT screen height and inclination effects on visual and musculoskeletal discomfort for Chinese wheelchair users with spinal cord injuries.

This study investigated the visual fatigue and musculoskeletal discomfort for wheelchair users in a VDT data entry task. Eight Chinese male wheelchair users were recruited as participants to perform 9 different experimental combinations. Three screen heights and three screen inclinations were evaluated. Visual fatigue was measured using the change in critical fusion frequency (CFF), near point accommodation (NPA) and a visual complaint questionnaire. Musculoskeletal discomfort was estimated using the rating of perceived exertion (RPE). Each participant performed a data-entry task within a 30 min period using random orders. All participants during the data-entry operation used the upright posture with the participant's lower and upper arms forming right angles. The results showed that the screen height and screen inclination significantly affected visual fatigue and musculoskeletal discomfort. On average, the optimal screen height choice for wheelchair users was at eye-level height or 5 cm below eye level with a vertical screen inclination.