An assessment of driving fitness in patients with visual impairment to understand the elevated risk of motor vehicle accidents

Abstract

ObjectiveTo assess the driving fitness of patients with glaucoma by identifying specific areas and degrees of visual field impairment that threaten safe driving.DesignCase–control study.Setting, and participantsThis prospective study included 36 patients with advanced glaucoma, defined as Humphrey field analyzer (HFA; 24-2 SITA standard program) measurements of mean deviation in both eyes of worse than −12 dB, and 36 age-matched and driving exposure time-matched normal subjects. All participants underwent testing in a novel driving simulator (DS) system. Participants were recruited between September 2010 and January 2012.Main outcome measuresThe number of collisions with simulated hazards and braking response time in 14 DS scenarios was recorded. Monocular HFA 24-2 test results from both eyes were merged to calculate the binocular integrated visual field (IVF). The position of the IVF subfields in which the collision-involved patients had lower sensitivity than the collision-uninvolved patients was compared with the track of the hazard. The cut-off value to predict an elevated risk of collisions was determined, as were its sensitivity and specificity, with the area under the receiver operating characteristic (AUROC) curve.ResultsPatients with advanced glaucoma were involved in a significantly higher number of collisions in the DS than the age-matched and driving exposure time-matched normal subjects (119 vs 40, respectively, p<0.0001), especially in four specific DS scenarios. In these four scenarios, IVF sensitivity was significantly lower in the collision-involved patients than in the collision-uninvolved patients in subfields on or near the track of the simulated hazard (p<0.05). The subfields with the largest AUROC curve had values ranging from 0.72 to 0.91 and were located in the paracentral visual field just below the horizontal.ConclusionsOur novel DS system effectively assessed visual impairment, showing that simulators may have future potential in educating patients.

A view on glaucoma—are we seeing it clearly?

“…54 We certainly need better evidence-based tests for determining those patients who are fit to drive and this might be determined by a variety of methods using driving simulators and collision data. [55][56][57][58] Other vision-related tasks also seem to be inhibited by glaucomatous visual field loss. The lighting conditions under which tasks are performed may be even more important that the task itself and this warrants further research.…”

Ocular disease and driving

“…A study by the same research group that included a larger sample of glaucoma patients with a wider range of field loss, showed that the drivers with glaucoma had more self‐reported and simulator crashes than controls and these were significantly related to the extent of the peripheral visual field. Similarly, a recent case‐controlled study reported that patients with advanced glaucoma (mean defect worse than ‐12 dB in both eyes) had significantly more simulator crashes in some driving scenarios, which were related to integrated visual field sensitivity; however, the drivers were not required to operate the steering wheel or the brake. In another small scale simulator study, drivers with glaucoma made more steering actions and were worse on a detection task than controls but there were no other between group differences; however, it should be noted, that there was no possibility of compensating for visual impairment in this study by reducing driving speeds as speed was fixed.…”

Predicting Future Self-Reported Motor Vehicle Collisions in Subjects with Primary Open-Angle Glaucoma Using the Penalized Support Vector Machine Method

“…Many studies have suggested a significant relationship between the deterioration in patients' VAs (and/or their VF) and driving ability. 28–37 However most of these studies assessed driving ability in an artificial situation. 28,37–41 For example, Crabb et al 39 investigated eye movements during a PC-based driving simulation and suggested that superior VF damage is disadvantageous for driving ability.…”

“…Tatham et al 37 investigated the relationship between MVCs in drivers with glaucoma and visual function, and found that the reaction times to low contrast divided attention tasks during driving simulation were significantly associated with a history of MVC. Kunimatsu et al 28 reported that patients with advanced glaucoma were involved in a significantly higher number of collisions in a driving simulator than controls. Szylk et al 40 reported that the number of accidents, measured in a driving simulator, in a glaucoma group was correlated significantly with peripheral VF extent.…”