An opportunity arose in 1985 to become involved in a transition of working practice from hard copy to VDT. Over a two-year period, 161 VDT users and 65 control subjects in the same office environment were regularly and routinely examined for symptoms of asthenopia. The analysis of data shows that there are no significant differences in type, number and frequency of the work-related symptoms between VDT users and non-VDT users. It appears that reporting of symptoms within the group may be random, although certain symptoms do appear more frequently than others. Additionally, it appears that there is a significant difference between male and female users in the frequency of symptom reporting.
A study is made of the accuracy and repeatability of the Humphrey autorefractor (HAR) objective refraction for different refractive groups as measured against subjective refraction. The value of the autofogging mechanism in objective refraction for different refractive groupings is assessed.
Since their rapid introduction into the workplace visual display terminals (VDT's) have been the source of a number of studies aimed at detecting effects on office workers. The published studies have been either short-term or cross-sectional, with one exception. The results have shown varying degrees of relation but by not having a comparable control group all have been limited in their value. We set out to monitor at regular intervals over a 2-year period specific visual functions that have been reported to be affected by VDT usage, and to compare VDT and non-VDT users in the same office environment. By assessing the VDT operators from the time the systems were introduced we have an accurate baseline to work from when assessing change due to the introduction of the VDT.
An on-site comparative study was carried out on the effects of video display terminal (VDT) and non-VDT work on visual functions in two working populations in the same office environment. Both continuous VDT usage in a training situation over a few days and intermittent VDT usage in a normal working situation were assessed and particular attention paid to their effects on the refractive error of different refractive groups and for different age populations. Other visual functions measured were visual acuity (VA), accommodation, and convergence. Results show that VDT work does not have a significantly greater effect on visual function than non-VDT work.