Luminance of the Surround and Visual Fatigue of VDT Operators

Agnieszka Wolska, Marcin Śwituła
1999 International Journal of Occupational Safety and Ergonomics  
Lum inance d istrib u tio n in the visual field is considered as one o f causal factors with a sig n ifica n t influence on visual fatigue, especially fo r intensive and extended Video D isplay Terminal (VDT) work. The aim of the study was to define visual fatigue o f VDT operators for different values of surrounding lum inance. Experiments were carried out in la b o ra to ry co n d ition s under 3 lig h t ing conditions. Only 1 lig h tin g param eter-the lum inance o f the w all behind the
more » ... lay (surrounding lum inance)-changed. Visual fatigue was measured both by a subjective evaluation of different visual com plaints (asthenopic symptoms) and by objective measurements of changes in the follow ing visual functions: accom m odation, convergence, habitual horizontal phoria, critical fusional frequency (CFF), and visual acuity. The same experiments were done for CRT (C athode Ray Tube) and LCD TFT (Liquid Crystal Display with Thin Film Transistor) screens. The results of the study have shown that there was no sig n ifica n t influence of the value of surrounding lum inance on the asthenopic sym ptom s for either type of screen. A general tendency tow ards bigger visual com plaints for LCD TFT than for CRT participants was found. An objective evaluation of visual fatigue demonstrated a tendency towards bigger changes in visual functio ns with an increase of surrounding lum inance fo r both screens. Statistical analysis o f the results has shown that surrounding lum inance influen ces significantly the reduction of the accom m odation am plitude (significance level < .05). lum inance visual fatigue CRT screen LCD TFT screen Correspondence and requests for reprints should be sent to Agnieszka Wolska,
doi:10.1080/10803548.1999.11076438 pmid:10657927 fatcat:7avoyzzubjgn5k7ymnflvm4w5q