Abstract
Purpose:
Visual field (VF) loss has been linked to driving ability among older adults, however there is ongoing debate regarding which specific VF regions are more strongly related to driving performance and safety. This study examined the associations between different VF measures and regions and on-road driving performance in older adults.
Methods:
Participants included 269 community-dwelling older drivers aged 70 years and older (M = 75.8 ± 3.9 years). Participants completed a battery of clinical vision tests of central vision (binocular logMAR visual acuity; Pelli-Robson contrast sensitivity) and visual fields (monocular 24-2 SITA-Standard; binocular Esterman field test). Binocular integrated visual fields (IVF) were derived from the maximum monocular sensitivity at each location to estimate central VF sensitivities. Driving performance was assessed in a dual-brake vehicle along a 19.4 km in-traffic suburban route. Overall driving safety was rated on a 10-point scale by a driver-trained occupational therapist masked to the visual status of the drivers, 148 driving manoeuvres were also rated with respect to 7 driving behaviours across 6 categories of traffic situations. Associations between the standard VF measures and IVF zones (central 5, central 10, 10 x 20, and full 200, and corresponding upper and lower zones) and driving performance were examined in bivariate analyses.
Results:
Of the clinical vision measures, reduced better-eye mean deviation (MD) was most strongly associated with poorer driving performance (r=0.23, p<0.001), followed by reduced worse-eye MD (r=0.18, p=0.004) and contrast sensitivity (r=0.17, p=0.005). Neither visual acuity nor the Esterman test were associated with driving performance (p>0.05). Of the IVF zones, reduced central 100 sensitivity was most strongly associated with poorer overall driving performance (r=0.31, p<0.001), and errors made on two-way roads, manoeuvring and merging traffic situations, as well as errors involving observation, approach planning and lane position (r=0.22 to 0.31, p<0.001). The lower IVF central 100 was consistently more strongly associated with these outcome measures than the upper zone.
Conclusions:
The results highlight the association between central binocular VF areas and on-road driving performance. These findings will assist in optimising VF measures to target those regions most relevant to on-road driving difficulties and safety in older adults.