[The influence of VDT work on accommodation]

In order to evaluate the influence of visual display terminal (VDT) work on accommodation, accommodation responses, such as accommodation latency, accommodation velocity, amount of accommodation and refractive power, were measured with an infra-red optometer (TER-7 NIDEK). Comparisons were also made between parameter before VDT work and after VDT work. At first, comparison of the accommodation responses of playing with a video game, being engaged in VDT work and paper work, was made in 5 subjects. There was no significant difference after playing with the video game, slight accommodative dysfunction occurred after being engaged in paper work, but the accommodative dysfunction was most remarkable after being engaged in VDT work. In the next study, the accommodation responses of 22 subjects engaged in VDT work were measured. It was found that there was no significant change in accommodation latency, but a decrease of contraction velocity and relaxation velocity for accommodation was observed, and also a decrease in the amount of contraction response and relaxation response for accommodation was observed. Myopic change during relaxation also occurred. These results suggested that VDT work induced accommodation dysfunction.