Effective medical examination of VDT workers using a new testing method of ocular alignment.

To investigate the relationship between asthenopia of VDT workers and the ocular alignment, we measured far and near alignment of 407 subjects (74 VDT workers with asthenopia, 137 VDT workers without asthenopia, and 196 non-VDT workers) using Total Vision tester (VT-500). There was no relationship between the asthenopia and the records of far alignment test. On the other hand, the incidence of exophoria and convergence insufficiency type in near alignment test was significantly high in the group of VDT workers with asthenopia. From these results, we speculate that cases who have exophoria or show incomplete fusional response measured under the near testing distance (50 cm) tend to complain of asthenopia.