A questionnaire survey was conducted on 271 workers of microelectronics company. The questionnaire included such items as age, years of service, working conditions and subjective symptoms related to visual, musculoskeletal and general status.
The following results were obtained:
a) Of these workers, approximately 80% operated visual display terminals (VDT). The years of service for most were less than 4 to 5 years with the average being about 2 years (Fig. 1). The working hours per day on the VDT for most of them was less than 90 min, although some workers operated VDT for 3 or more hours per day (Fig. 2).
b) A high incidence of complaints of visual function, i.e. eye strain and blurring of distant objects, was observed. Some also complained of musculoskeletal and general symptoms (Table 1).
c) The rates of these subjective symptoms increased with years of service (Figs. 4 and 5), while the complaint rates decreased with age (Fig. 3). Significant positive correlations were found between most of these complaint rates and length of service (Table 2), although correlations between the complaint rates and age were generally non-significant but negative.
d) The complaints tended to increase with working hours per day, although the operators who worked for longer period per day did not seem to complain as much as those who did not work so long (Fig. 6).
In conclusion, the results of this questionnaire suggest that the effects of visual display terminals (VDT) work accumulate gradually over months and years.
