Abstract
Purpose:
To characterize the driving difficulties of older adults with glaucoma using a standardized on-road assessment and to determine the best visual predictors of on-road driving ability.
Methods:
In this ongoing study, 59 participants aged 65 years and older with glaucoma (M = 72.9 ± 5.6 years) and 65 normal controls (M = 72.3 ± 4.5 years) have been tested; glaucoma participants had mild to moderate levels of visual field loss (better-eye MD = -1.19 dB ± 5.12 (-23.24 to 3.99 dB); worse-eye MD= -7.95 dB ± 8.67 (-31.00 to 2.10 dB)). Participants completed a battery of vision function tests including visual acuity, contrast sensitivity, visual fields, three measures of motion sensitivity (Gabor motion sensitivity and random dot motion sensitivity using both small and large dots) and a test of the useful field of view. On-road driving performance was assessed in a dual-brake vehicle along a 19.4 km route. Overall driving safety was rated on a 10-point scale by a driver-trained occupational therapist who was masked to the ocular status of the drivers, 148 driving manoeuvres were also rated with respect to seven driving behaviours across six traffic situations. Participants also completed an ongoing diary of driving incidents.
Results:
There were significant between group differences in terms of total errors, proportion of locations without error, and number of instructor interventions. Glaucoma participants made more errors at traffic lights, give-way intersections and in dual-carriageway driving, and had more errors involving lane position and gap selection (such as accurately judging distances and speeds when entering traffic or changing lanes). Motion perception was the best visual predictor of the overall driver safety rating, as well as the number of critical driving errors. A multiple regression model including age as a covariate and visual measures as predictors, found that motion sensitivity was the only unique significant predictor of overall driving safety rating.
Conclusions:
These findings assist in characterizing the driving difficulties of patients with glaucoma and provide information regarding the visual predictors of driving problems in this population. As such, these findings may have important implications for training and remediation of older drivers with visual impairment.
Keywords: 414 aging: visual performance •
753 vision and action