Association of visual sensory function and higher-order visual processing skills with incident driving cessation

Many studies on vision and driving cessation have relied on measures of sensory function, which are insensitive to the higher-order cognitive aspects of visual processing. The purpose of this study was to examine the association between traditional measures of visual sensory function and higher-order visual processing skills with incident driving cessation in a population-based sample of older drivers.

Two thousand licensed drivers aged 70 years or older were enrolled and followed for three years. Tests for central vision and visual processing were administered at baseline and included visual acuity, contrast sensitivity, sensitivity in the driving visual field, visual processing speed (useful field of view [UFOV] Subtest 2 and Trails B) and spatial ability measured by the Visual Closure Subtest of the Motor-free Visual Perception Test. Participants self-reported the month and year of driving cessation and provided a reason for cessation. Cox proportional hazards models were used to generate crude and adjusted hazard ratios with 95% confidence intervals between visual functioning characteristics and risk of driving cessation over a three-year period.

During the study period, 164 participants stopped driving, which corresponds to a cumulative incidence of 8.5 per cent. Impaired contrast sensitivity, visual fields, visual processing speed (UFOV and Trails B) and spatial ability were significant risk factors for subsequent driving cessation after adjusting for age, gender, marital status, number of medical conditions and miles driven. Visual acuity impairment was not associated with driving cessation. Medical problems (63 per cent), specifically musculoskeletal and neurological problems, as well as visual problems (17 per cent) were cited most frequently as the reason for driving cessation.

Assessment of cognitive and visual functioning can provide useful information about subsequent risk of driving cessation among older drivers. In addition, a variety of factors, not just vision, influenced the decision to stop driving and may be amenable to intervention.