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Original Investigation
April 29, 2021

Naturalistic Driving Techniques and Association of Visual Risk Factors With At-Fault Crashes and Near Crashes by Older Drivers With Vision Impairment

Author Affiliations
  • 1School of Medicine, Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham, Birmingham
  • 2School of Public Health, Department of Epidemiology, University of Alabama at Birmingham, Birmingham
  • 3Center for Vision and Eye Research, School of Optometry and Vision Science, Queensland University of Technology, Brisbane, Queensland, Australia
  • 4Vulnerable Road User Safety, Virginia Tech Transportation Institute, Blacksburg
JAMA Ophthalmol. Published online April 29, 2021. doi:10.1001/jamaophthalmol.2021.0862
Key Points

Question  What are visual risk factors associated with at-fault crashes and near crashes by older drivers with age-related eye conditions objectively assessed by naturalistic driving methods using video-confirmed events?

Findings  This cohort study of 154 drivers 70 years or older found that vision impairment in contrast sensitivity, processing speed, and motion perception at baseline was moderately associated with the rate of at-fault crashes and near crashes during the subsequent 6 months of driving.

Meaning  Motor vehicle crash reports used in the study of driver safety are frequently biased and incomplete; this study avoids these shortcomings by documenting vision impairment characteristics associated with collision risk among older drivers with age-related eye conditions by using naturalistic driving methods.


Importance  Government motor vehicle crash reports used in the study of driver safety can be biased and incomplete. Naturalistic driving methods using in-vehicle instrumentation have been developed in recent years to objectively measure crashes and near crashes as they occur on the road using video and vehicle kinematic data.

Objective  To examine visual risk factors associated with at-fault crashes and near crashes among older drivers, most of whom have age-related eye conditions associated with vision impairment.

Design, Setting, and Participants  This prospective cohort study was conducted at an academic ophthalmology clinic from January 1, 2015, to November 10, 2018, among 154 adults 70 years of age or older who were legally licensed in Alabama and who reported currently driving at least 4 days per week; 137 of 151 participants (90.7%) had an age-related eye condition in at least 1 eye. Drivers participated in a baseline visual function assessment followed by installation of a data acquisition system recording multichannel synchronized video and vehicle kinematics in their personal vehicle. Drivers were instructed to drive for 6 months as they normally would during everyday life. Statistical analysis was performed from June 15 to September 15, 2020.

Main Outcomes and Measures  The rate of combined incident at-fault crashes and near crashes, defined by the number of events and the number of miles driven.

Results  The sample consisted of 154 drivers (85 men [55.2%]; mean [SD] age, 79.3 [5.1] years). Visual functions associated with crash and near-crash involvement included impaired contrast sensitivity (rate ratio [RR], 2.7; 95% CI, 1.3-5.5), moderate (RR, 2.3; 95% CI, 1.1-4.9) and severe (RR, 5.0; 95% CI, 2.2-11.7) slowing in visual processing speed, and elevated motion perception thresholds for a drifting grating (RR, 1.9; 95% CI, 1.1-3.5). Those with impaired peripheral visual field sensitivity had increased rates of crashes and near crashes (RR, 1.8; 95% CI, 1.0-3.3); however, this finding was not statistically significant (P = .07).

Conclusions and Relevance  With the use of naturalistic driving methods in which crashes and near crashes involving older drivers are objectively measured as they occur on the road, associations have been identified between impaired contrast sensitivity, slowed visual processing speed, and impaired motion perception and an increased rate of a combined total of at-fault crashes and near crashes.

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    1 Comment for this article
    Visua Impairment and MVAs.
    Charles brill, MD | Thomas Jefferson University
    Did any of these drivers also have cognitive impairment?