Abstract
We determined whether binocular central scotomas above or below the preferred retinal locus affect detection of hazards (pedestrians) approaching from the side. Seven participants with central field loss (CFL), and seven age-and sex-matched controls with normal vision (NV), each completed two sessions of 5 test drives (each approximately 10 minutes long) in a driving simulator. Participants pressed the horn when detecting pedestrians that appeared at one of four eccentricities (-14°, -4°, left, 4°, or 14°, right, relative to car heading). Pedestrians walked or ran towards the travel lane on a collision course with the participant’s vehicle, thus remaining in the same area of the visual field, assuming participant's steady forward gaze down the travel lane. Detection rates were nearly 100% for all participants. CFL participant reaction times were longer (median 2.27s, 95% CI 2.13 to 2.47) than NVs (median 1.17s, 95%CI 1.10 to 2.13; difference p<0.01), and CFL participants would have been unable to stop for 21% of pedestrians, compared with 3% for NV, p<0.001. Although the scotomas were not expected to obscure pedestrian hazards, gaze tracking revealed that scotomas did sometimes interfere with detection; late reactions usually occurred when pedestrians were entirely or partially obscured by the scotoma (time obscured correlated with reaction times, r = 0.57, p<0.001). We previously showed that scotomas lateral to the preferred retinal locus delay reaction times to a greater extent; however, taken together, the results of our studies suggest that any binocular CFL might negatively impact timely hazard detection while driving and should be a consideration when evaluating vision for driving.
Highlights
Driving is the primary means of transportation in the U.S.[1] and driving cessation may reduce quality of life [2]
central field loss (CFL) participants were delayed enough that they would not have been able to stop for 21% of the pedestrians, seven times more than Normal Vision (NV) participants, even though pedestrians appeared at twice the recommended perception-brake sight distance (2x2.5s travel time) [22]
CFL participants responded later to pedestrians than NV controls, and their latencies were similar to lateral CFL participants in our prior study (2.46s) [14]
Summary
Driving is the primary means of transportation in the U.S.[1] and driving cessation may reduce quality of life [2]. We reported that CFL lateral (to the left or right) to the PRL markedly delayed reactions to pedestrian hazards approaching from the scotoma side [14]. We report driving simulator results from participants with vertical CFL: binocular scotomas above or below their PRL. Because pedestrian hazards typically appear on the side of the road and likely outside the vertical scotoma, we hypothesized that detection rates and reaction times would be similar for pedestrians approaching from the right or left. For drivers with vertical CFL, it is possible that typical vertical gaze movements used when driving (e.g., to glance at the dashboard) might occasionally place on-road hazards, normally imaged on intact peripheral retina, into a scotoma and thereby delay detection. We used gaze-tracking, and the position, size, and shape of each participant’s scotoma, to test this hypothesis
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
