Bifocal/varifocal spectacles, lighting and missed-step accidents

Good lighting and the correct use of spectacles generally improve vision an d presumably reduce the risk of accidents. However, bifocal and varifocal s pectacles can increase the risk of misjudging distances when negotiating un derfoot hazards. In some circumstances, the portion of the lens used for cl ose work may inadvertently be used where accurate judgement of distance is necessary. This paper reports results from two studies of patient interview s using the Merseyside Accident Information Model; the first a study of acc idents which occurred during paid employment (1504 cases) and the second of 1326 accidents mainly in domestic and leisure activities. Underfoot accide nts were identified by the first unforeseen event perceived by the patient. The relationship between underfoot events and the type of spectacles worn by the patient at the time of accident was analysed. In both studies there was a significant association between accidents where the first event was ' missed edge or (step) and wearing bifocal/varifocal spectacles. Corporal mo vements reported in both studies indicated that 'stepping down' when wearin g bifocal/varifocal spectacles, increased the risk of 'missed edge' acciden ts. In the work environment corporal movements associated with manual handl ing of loads also increased the risk of 'missed edge' accidents when wearin g bifocal/varifocal spectacles. (C) 2001 Elsevier Science Ltd. All rights r eserved.