Bifocal wearing and VDU operation: A review and graphical analysis

There has been a lack of expert guidance regarding the visual capabilities of VDU operators who wear bifocal spectacles. The authors have developed a general framework as a basis for analysing the problem. A schematic diagram has been constructed which facilitates the integration of the variables of lens dimensions, range of clear vision and a standard VDU workstation. The analysis of the diagram established that the majority of bifocal wearers are able to operate a VDU efficiently without special optical considerations. However, a prima facie case was found to exist for some VDU operators wearing bifocal spectacles and experiencing problems. These operators are most likely over 50 years of age, usually over 55 years of age and, in principle, comprise a small proportion of the workforce. Vocational prescribing for this group must be viewed sympathetically in order to avoid the increased risk of bodily injury.