The Center for Healthy Aging is hosting a special interest group (Aging SIG) in aging for graduate students, post-doctoral researchers, and faculty interested in the study of aging. The group will provide a forum for researchers to discuss their own research and to learn from others on the topic of aging from interdisciplinary perspectives.
Visual Field Loss and Change Blindness When Driving
Dr. Garrett Swan
Postdoctoral Fellow, Schepens Eye Research Institute
Harvard Medical School
Individuals with visual field loss, such as those with homonymous hemianopia (i.e. loss of vision on one side in both eyes), are permitted to drive in many states. Thus, it is important to know what the consequences of a visual field loss are on driving safety. A critical aspect of driving safety is the ability to detect and respond to potential hazards. There is increasing evidence that when a driver with a visual field loss fails to scan (look from side to side) and a hazard falls within the area of the field loss, then the hazard may not be detected or may be detected very late, which could be unsafe. There is one class of detection failure that has not been systematically investigated in drivers with visual field loss – specifically, failing to be aware of a hazard that is clearly seen. Failures of visual awareness may manifest as “looked but failed to see” incidents, which are commonly reported motor vehicle accidents where the driver fails to detect another road user despite looking in the direction of the other road user. We evaluated failures of awareness using a change blindness paradigm in a driving simulator where participants were tasked with detecting pedestrians that changed location. Failing to detect the changed position of the pedestrian corresponded to change blindness, which is the failure to be aware of large changes. We found more change blindness in individuals with hemianopia than healthy controls. Furthermore, we found change blindness in both the seeing and blind visual fields in the individuals with hemianopia. These results suggest that having a visual field loss may make one more susceptible to failures of awareness.