Abstract
Purpose::
To investigate the on-road driving performance of glaucoma patients compared to age and gender matched control subjects with normal vision.
Methods::
The sample comprised 15 glaucoma patients (mean visual field MD better eye = -1.7 dB, range -5.9 to +0.7 dB; mean visual acuity [VA] better eye = 0.05 logMAR, range -0.10 to 0.20 logMAR) and 15 control subjects, who were enrolled in an ongoing study of risk factors for falls and motor vehicle collisions in glaucoma. On-road driving performance was tested over a 10 km route incorporating 55 maneuvers through residential and business districts. Testing was conducted by a professional driving instructor and assessed by an occupational therapist experienced in driving rehabilitation. Neither the instructor nor the occupational therapist had any knowledge regarding the glaucoma status or visual functions of the participants. Main outcome measures were number of maneuvers correctly executed, overall rating, and number of critical errors requiring the driving instructor to intervene by using the dual brake control. Visual functions measured were VA (ETDRS logMAR) and visual fields (Humphrey Field Analyzer [HFA] SITA 24-2 and binocular Esterman).
Results::
There was no significant difference between glaucoma patients and control subjects in the number of maneuvers correctly executed, or overall rating of driving performance (P = 0.82 and 0.40, respectively). However, glaucoma patients were over 5 times more likely to make one or more critical errors compared with control subjects (odds ratio [OR] = 5.50, 95% CI 1.15 to 26.41). In 80% of cases the critical error was failure to yield to a pedestrian. An HFA MD of less than -5.0 dB in the worse eye was strongly associated with such errors (OR = 2.50, 95% CI 1.17 to 5.34).
Conclusions::
Although glaucoma patients perform many real-world driving maneuvers adequately, compared to healthy control subjects, they may be more likely to have incidents involving pedestrians.
Keywords: visual fields • clinical (human) or epidemiologic studies: risk factor assessment • aging: visual performance