Poorer driving performance in glaucoma patients
Overall driving performance is reduced in older drivers with glaucoma, even in those with only mild to moderate field loss, a new study reports. Specifically, these individuals encounter problems in complex situations requiring foresight and observation.
For the study, 75 patients diagnosed with glaucoma were recruited. A parallel, age-matched cohort of 70 healthy controls with normal eyesight was also established. For inclusion in either group, participants had to be current and licensed drivers in Australia. Those who had other conditions that affects vision, had a history of dizziness, had Parkinson’s Disease, showed signs of cognitive impairment, or used a walking aid were excluded from the study.
Each participant underwent an eye examination which included the following tests: slit-lamp biomicroscopy, ophthalmoscopy, and fundus photography. Additionally, they were asked to accomplish the Driving Habits Questionnaire which describes their driving habits, the frequency of driving, and the difficulties encountered. The questionnaire also includes a self-assessment of driving ability.
For the driving assessment, each participant was asked to drive along a specified route using an automatic, dual-break vehicle. A professional driving instructor, seated at the front seat, gave instructions to the participants as they drove. The route included different kinds of intersections and different roads which ensured a wide variety of traffic situations.
In addition to the driving instructor, an experienced occupational therapist, seated at the back, was in charge of scoring and rating the driving performance of the participants. Driving errors, locations where they were made, and critical errors were recorded by the occupational therapist.
Generally, drivers suffering from glaucoma committed more driving errors than the control counterparts. Moreover, the number of critical errors in the glaucoma group is almost double than that in the control group.
Much of the errors were in situations that required advanced planning and lane positioning. In terms of location, most of the errors occurred mostly at traffic lights and at yield intersections.
Overall the data show that driving performance suffers in older drivers with glaucoma. This poses a problem especially since the drivers self-report their driving as relatively good. Thus, a more objective and quantifiable basis for evaluating driving performance is needed.