Studies on the evaluation of visual fatigue in VDT work by involuntary eye movement (flick)

• Published in: Ningen kogaku. The Japanese journal of ergonomics Vol. 32; no. 2; pp. 87 - 97
• Main Authors: SAKAMOTO, Kazuyoshi, Gu, Li Gang
• Format: Journal Article
• Language: English
• Published: Japan Ergonomics Society 1996
• ISSN: 0549-4974; 1884-2844
• DOI: 10.5100/jje.32.87

In order to evaluate visual fatigue of VDT (Visual Display Terminals) operators, flick movement in involuntary eye movement during binocular fixation on the small target is measured before and after 2-hours VDT workload (visual search task) by a photo-electric recording of corneal reflection. An emphasis is put on analyses on variation of flick in which horizontal components of frequency, interval, amplitude and velocity are obtained. For 2-hours VDT work, the significant decrease in frequency, amplitude and velocity of flick and the significant increase of interval of flick are observed with the level of 1%. Near point distance (NP), subjective symptoms and performance are also measured during VDT work. NP and the subjective symptoms show the visual fatigue. The correlation between increase of NP and change of flick characteristics is recognized. It is concluded that the variation of components obtained in flick is the effective index to evaluate the visual fatigue which manifests not physical aspect but mental aspect for subject.