Abstract
Visual field requirements for driving vary widely and are largely without scientific basis. While some states specify a minimum horizontal binocular field extent (e.g., 120° in MA), others have no field requirements (e.g., NH), and some have monocular field requirements. Other countries, such as the UK and Australia, have requirements addressing both the integrity of the central visual field and the peripheral extent. This talk will review the results of studies which have started to address some of the existing knowledge gaps about the impact of field loss on driving performance. An essential consideration is whether a person with field loss is able to detect hazards in a timely manner, in particular, those hazards which first appear in non-seeing areas of the field. This is difficult to evaluate in an open-road driving situation where there is no control over if, where, or when hazards might appear. However, a series of driving studies in the safe, controlled, repeatable environment of a driving simulator has provided important insights into the effects of field loss on hazard detection. (1) Compensatory eye/head scanning is often inadequate resulting in missed detections or delayed responses, even when participants are highly primed to the hazard appearance. (2) The extent of compensatory eye/head scanning varies widely despite similar amounts of remaining visual field, suggesting that we need to evaluate more than just horizontal field extent. (3) The presence of central field loss should be taken into account when developing vision requirements for driving because central scotomas delay responses to hazards.
Meeting abstract presented at the 2016 OSA Fall Vision Meeting