Short-Term Changes in Eyestrain of VDU Users as a Function of Age

Operators at a Swedish Telecom Directory Enquiry Centre participated in tests of eyestrain including measures of accommodation and convergence near points, focusing accuracy, and dark focus. The optometric measurements were conducted before and after work at a visual display unit (VDU) and in two control conditions, with or without job rotation. Visual focus of accommodation was measured with a modified version of the field laser optometer method. The results showed no differential eyestrain effects, either in near points of accommodation and convergence or in focusing accuracy, between the three tasks. A small, age-dependent difference in dark focus was apparent after work in the job-rotation phase. It is concluded that the VDU work was not in itself conducive to eyestrain, and that, under the job conditions obtained in the present investigation, changes in the variables studied must be primarily attributed to other factors, such as age and workload on the day of testing.