In a realistic pedestrian detection task, drivers with HH exhibited significant blind-side detection deficits. Even when approaching pedestrians were detected, responses were often too late to avoid a potential collision.

This study aimed to further our understanding of the impact of a restricted field of view on visual search and hazard perception, by comparing novice and experienced driver performance in a driving simulator as a function of the available field of view. Participants encountered a series of virtual hazards during their drive while viewing the world under narrow or wide field of view conditions.The results showed that all drivers were more likely to avoid the hazards when presented with a wide view, even though the hazards only occurred in an area of the screen that was visible in both the wide and narrow view conditions. Experienced drivers also tended to have fewer crashes, and this appeared to be related to a greater speed reduction 10 metres before the hazard. This speed reduction was greatest in the wide field of view condition suggesting that additional information from wider eccentricities was useful in safely navigating the hazardous events. Gaze movement recording revealed that only experienced drivers made overt use of wider eccentricities, and this was typically in advance of any visual cues that might help identify the hazard. This suggests that either early overt attention to wider eccentricities, or continuous covert attention to these extrafoveal regions on approach to the hazard, is responsible for the safer behaviour of experienced drivers when presented with a wide field of view. We speculate about the possible underlying mechanism and discuss possible consequences for HP tests.

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PurposeThe ability of visually impaired people to deploy attention effectively to maximize use of their residual vision in dynamic situations is fundamental to safe mobility. We conducted a pilot study to evaluate whether tests of dynamic attention (multiple object tracking; MOT) and static attention (Useful Field of View; UFOV) were predictive of the ability of people with central field loss (CFL) to detect pedestrian hazards in simulated driving.Methods11 people with bilateral CFL (visual acuity 20/30-20/200) and 11 age-similar normally-sighted drivers participated. Dynamic and static attention were evaluated with brief, computer-based MOT and UFOV tasks, respectively. Dependent variables were the log speed threshold for 60% correct identification of targets (MOT) and the increase in the presentation duration for 75% correct identification of a central target when a concurrent peripheral task was added (UFOV divided and selective attention subtests). Participants drove in a simulator and pressed the horn whenever they detected pedestrians that walked or ran toward the road. The dependent variable was the proportion of timely reactions (could have stopped in time to avoid a collision).ResultsUFOV and MOT performance of CFL participants was poorer than that of controls, and the proportion of timely reactions was also lower (worse) (84% and 97%, respectively; p = 0.001). For CFL participants, higher proportions of timely reactions correlated significantly with higher (better) MOT speed thresholds (r = 0.73, p = 0.01), with better performance on the UFOV divided and selective attention subtests (r = −0.66 and −0.62, respectively, p<0.04), with better contrast sensitivity scores (r = 0.54, p = 0.08) and smaller scotomas (r = −0.60, p = 0.05).ConclusionsOur results suggest that brief laboratory-based tests of visual attention may provide useful measures of functional visual ability of individuals with CFL relevant to more complex mobility tasks.