The present study is the fourth of a major epidemiologic health investigation on work with a video display terminal (VDT). The other studies showed that VDT operators replying to questionnaires have more eye discomfort than a reference group of office employees not employed in VDT work and that women have more eye discomfort, musculoskeletal complaints, headache, and skin disorders than men. Routine ophthalmologic examinations failed to establish any appreciable differences between the groups; for example, the prevalence of myopia was the same. In the present study, the VDT operators and referents were examined before and at the end of work sessions for changes in refraction, accommodation, convergence capacity, and binocular vision such as heterophoria and fusion range. No differences could be established between the VDT operators and the referents.