Pupillary changes due to work using visual display terminals.

ABSTRACT

In order to measure the degree of ocular fatigue and general fatigue among the workers using visual display terminal (VDT), pupillary dynamics were measured with open-loop light stimulation for 26 subjects of a mean age of 25.9 years. VDT loads were TV games for 30 min under indirect light of 100 lux. The eight parameters of pupillary light reflex with open-loop pupillometer were examined before and after VDT loads. On the right eyes, two parameters and one value increased 9.2% (Student's t-test P less than 0.005, max.), 25.7% (Student's t-test P less than 0.005, Min.) and 14.8% (Student's t-test P less than 0.005, min/max) just after the load and then gradually decreased and returned to the pre-load level after a 10 to 15-min rest period. Two parameters increased 11.7% (Student's t-test P less than 0.05, 1/2C) and 12.9% (Student's t-test P less than 0.05, VD), one parameter decreased -9.0% (Student's t-test P less than 0.05, 0.63D) and three parameters were constant (Student's t-test L, A and VC) just after the load. On the left eyes, the same tendencies were observed. But there were no significant differences (Student's t-test) between the right and left eyes. The change pattern of the eight parameters were small in degree and similar to the changes when the sympathetic nervous system was activated.