Eye-strain and changes in accommodation of the eye and in visual evoked potential following quantified visual load

Publisher Website
Google Scholar
Abstract
The measurements were made of the muscular contractions and relaxations of accommodation (infrared optometer) and of visual evoked potential (VEP) (photic stimulation) before and after one hour's visual load, checking calculations (1800 questions/hour and 900 questions/hour). The results showed that the relaxation time in accommodation lengthened and the latency of the positive wave appearing at about 100 ms in VEP increased with the increase in visual load. In addition, the complaint rate for eye-strain was higher in the group given heavier visual work. In this group, there was no significant difference in amplitude of VEP before and after the visual task. The difference in the relaxation time before and after the visual task tended to be negatively correlated to the difference in amplitude of VEP and positively related to that in the latency. In the group given lighter visual work there were significant differences in the latency and the amplitude of VEP before and after the visual task, neither were correlated to the difference in the relaxation time. These results suggest that not only peripheral hypofunction but also the decrease of centrencephalic activity level may be responsible for the development of eye-strain caused by visual tasks.