On-Road Driving Performance by Persons with Hemianopia and Quadrantanopia

Abstract

Purpose This study was designed to examine the on-road driving performance of drivers with hemianopia and quadrantanopia compared with age-matched controls. Methods Participants included persons with hemianopia or quadrantanopia and those with normal visual fields. Visual and cognitive function tests were administered, including confirmation of hemianopia and quadrantanopia through visual field testing. Driving performance was assessed using a dual-brake vehicle and monitored by a certified driving rehabilitation specialist. The route was 14.1 miles of city and interstate driving. Two “back-seat” evaluators masked to drivers’ clinical characteristics independently assessed driving performance using a standard scoring system. Results Participants were 22 persons with hemianopia and 8 with quadrantanopia (mean age, 53 ± 20 years) and 30 participants with normal fields (mean age, 52 ± 19 years). Inter-rater agreement for back-seat evaluators was 96%. All drivers with normal fields were rated as safe to drive, while 73% (16/22) of hemianopic and 88% (7/8) of quadrantanopic drivers received safe ratings. Drivers with hemianopia or quadrantanopia who displayed on-road performance problems tended to have difficulty with lane position, steering steadiness, and gap judgment compared to controls. Clinical characteristics associated with unsafe driving were slowed visual processing speed, reduced contrast sensitivity and visual field sensitivity. Conclusions Some drivers with hemianopia or quadrantanopia are fit to drive compared with age-matched control drivers. Results call into question the fairness of governmental policies that categorically deny licensure to persons with hemianopia or quadrantanopia without the opportunity for on-road evaluation.

Hazard Detection by Drivers with Paracentral Homonymous Field Loss: A Small Case Series

“…The findings of this and other recent studies [3,14] indicate the importance of individualized evaluations, as the functional abilities of two people with similar vision loss can differ widely. In recent years the UK [4] and Quebec, Canada [5] have permitted licensing following successful on-road driving evaluations for patients with hemianopia who do not meet minimum horizontal visual field Figure 4: Case 3's eye-gaze data for two pedestrians at the large right eccentricity (median filtered with a 5-frame window, 60 Hz).…”

Characteristics of On-Road Driving Performance of Persons With Central Vision Loss Who Use Bioptic Telescopes

“…Performance was rated by two independent ''backseat evaluators'' at 41 locations along the route on a previously developed 3-point scale, 20 with respect to eight different behaviors/skills; 28 locations were in suburban streets, 11 on a multilane highway, and 2 in city streets. One backseat evaluator, designated as the primary evaluator, sat in the middle of the backseat (positioned so that the evaluator did not obscure the driver's view of the rearview mirror), with the second evaluator sitting behind the driver.…”

Compensatory eye and head movements of patients with homonymous hemianopia in the naturalistic setting of a driving simulation

“…We assessed visual fields monocularly using automated 30°threshold perimetry (30-2 strategy, Swedish interactive threshold algorithm ''SITA'', including 76 visual field positions within the central 30 degrees of the visual field), and automated 80°perimetry (including 101 visual field positions) using a Humphrey Field Analyzer II (Carl Zeiss Meditec Inc., Dublin, CA). We classified the homonymous visual field loss based on the 30°threshold perimetry as complete or incomplete in accordance with a recent study by Wood and colleagues [8]. Furthermore, we quantified the visual field defect identifying the number of visual field locations that were not detected by patients in the 80°perimetry.…”

“…One aspect of daily living in which the impairment of visual exploration of the natural environment becomes most evident is driving a car. Studies examining the question, whether patients with HH can be rated safe to drive, with on-road assessments have produced inconclusive results with safe ratings ranging from 14 to 73 % of tested patients [8][9][10]. A major challenge with on-road driving tests, however, is the lack of standardized conditions (e.g.…”