The effect of downward gaze.
Knut Inge Fostervold and Ivar Lie Department of Psychology, University of Oslo. P.O.box 1094 Blindern N-0317 Oslo, Norway. e-mail: firstname.lastname@example.org
Over the last fifteen years information technology and the use of visual display units (VDU) have become a predominant device in the industrialised world. Due to its rapid implementation very little was known about possible health risks ensuing from prolonged interactive VDU work. This fact led to immense interest among scientists and health professionals, when reports about adverse health reactions started to appear ( Dainoff and Happ 1981, Grandjean 1984).
Initially, eye problems and musculoskeletal problems were the main focus of interest. At that time, ergonomists were fairly acquainted with health problems caused by sedentary and repetitive work. Since most VDU-operations are sedentary, necessitating repetitive body movements and constrained postures, earlier data, especially from typists, were used as a frame of reference. Visual and oculomotor consequences of sustained excessive near-work have been research topics in visual perception and optometry for almost 50 years ( Brozek et al. 1950, Tyrrell and Leibowitz 1991). Since typical VDU-work tasks are dominated by intensive visual work at short range, renewed interests in these issues were a logical consequence. Other health problems discussed in the literature are psychosocial factors, concentration problems, symptoms of skin irritation, headache, dizziness and general fatigue ( Grandjean 1984, Bergqvist et al. 1992). However, in spite of considerable scientific and ergonomic effort many VDU operators still experience physiological problems related to their work.
Consequently, several guidelines have been developed recommending preventive and remedial actions for the VDU workplace. A recommendation that has achieved widespread acceptance is the high monitor placement in which the VDU-screen is positioned slightly below eye level. In this position, the midpoint of the screen requires a gaze angle approximately 10°- 20° below the horizontal line. Recently, this recommendation has been challenged. Today, a growing