Abstract
Purpose :
Drivers with glaucoma show increased driving safety risk. We tested the hypothesis that binocular visual field loss affects driving performance and self-reported driving in glaucoma.
Methods :
We studied 17 drivers: 7 with glaucomatous field defects (Visual field index (VFI) range: 21-97%) and 10 glaucoma suspects with full fields. Binocular VFI (VFI-OU) was calculated using integrated monocular fields from the Humphrey Visual Field (HVF) Analyzer. Subjects were tested in an immersive driving simulator (full car, interactive controls, 290° forward field of view) in driving scenarios on an empty highway with a concurrent in-simulator visual field task (Anderson 2017, https://doi.org/10.17077/drivingassessment.1607). Driving metrics were acceleration (lateral, longitudinal), steering wheel position, accelerator pedal position, and velocity. The National Eye Institute 25-Item Visual Function Questionnaire (NEI-VFQ) indexed driver self-reported visual quality of life (global and driving subscale scores). Group comparison used independent-sample t-tests. Pearson correlations evaluated the relationship between VFI-OU, driving metrics and NEI-VFQ scores across all subjects.
Results :
While glaucoma subjects were older (74 v 57 years, p<0.05), age was not significantly correlated (p>0.10) with VFI-OU, NEI-VFQ global or driving scores. Glaucoma group had significantly (p<0.05) lower NEI-VFQ driving scores (74 v 90) and global scores (83 v 92) and higher lateral acceleration variability (0.008 v 0.003) compared to the comparison group. Other driving metrics did not differ significantly between groups.
Decreased VFI-OU was associated (p<0.05) with increased steering wheel position variability (r= -0.54), lateral acceleration variability (r= -0.62) and decreased NEI-VFQ global score (r= 0.52). Increased global NEI-VFQ score was associated (p<0.05) with increasing maximum velocity (r=0.48). Decreased NEI-VFQ driving score was associated (p<0.05) with increased steering wheel position variability (r= -0.64) and lateral acceleration variability (r= -0.54).
Conclusions :
Binocular field deficits and self-reported driving performance correlated with poorer vehicle control measures even in the absence of on-road hazards. These results suggest a categorical glaucoma diagnosis (with a wide range of disease severity) may not be as sensitive to driving performance as VFI-OU.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.