Objective
For hemianopia, peripheral prisms (p-prisms) expand the visual field up to 40° on standard perimetry (Jung and Peli, 2014). In prior studies, p-prisms improved self-reported mobility scores over a sham in a randomized controlled clinical trial (Bowers, 2013) and improved responses to hazards in a pilot on-road study. However, gaze was not tracked in either of these studies and there was no control over when or where hazards appeared. We therefore conducted a study to objectively measure detection and gaze behavior with the p-prisms in the controlled environment of a driving simulator.
Design
Prospective, within-subjects, before-after trial.
Setting
Massachusetts Eye and Ear Infirmary Vision Rehabilitation Laboratory in a wide-field (225°) driving simulator.
Participants
Referred hemianopia without neglect (n=11), >3 months after brain-injury, for a protocol approved by the Massachusetts Eye and Ear IRB.
Interventions
Measurements were performed without p-prisms at baseline and with p-prisms after training and
Main Outcome Measure(s)
Detection rates and reaction times for pedestrians appearing on the right (n=26) or left (n=26) of the roadway during five 10-minute drives.
Results
Mean blindside detection improved from 47% to 72% (p=0.001) and reaction time from 3.0s to 2.4s (p=0.036), but still was not equal to seeing side performance (100% and 1.1s). Between-subject variability in blindside detection was considerable (SD ±26%). Preliminary analysis of gaze tracking supports detection on multiple occasions via p-prisms.
Conclusions
These data provide preliminary evidence of improved detection during driving via p-prisms. The wide-between subject variability in detection performance without and with p-prisms highlights the importance of individualized assessment of hemianopia in a multidisciplinary driver-rehab program.
Key Words
Hemianopia, Prisms, Driving, Homonymous, Hemianopsia
Disclosure(s)
Dr. Eli Peli has a patent on the peripheral prisms through the Massachusetts Eye and Ear Infirmary Schepens Eye Research Institute.
Article Info
Publication History
Poster 38
Identification
Copyright
© 2014 Published by Elsevier Inc.
