Study shows drivers with glaucoma at increased crash risk
A study based on a closed-road driving assessment found that older drivers with glaucoma have poorer driving performance and a higher crash risk than subjects without the disease
The study, performed at the Queensland University of Technology optometry clinic, Australia, included 13 participants with glaucoma and 10 healthy controls. Preliminary testing included visual acuity, contrast sensitivity, visual field and motion sensitivity.
Driving assessment was conducted in daylight on a 4.7 km closed-road circuit, including hills, bends and straight stretches with two and three lanes. The research vehicle was equipped with two roof-mounted cameras. Two experimenters sat with subjects in the vehicle to provide instructions and operate an eye and a head tracker.
A series of large, gray low-contrast hazards made of thick foam were placed around the circuit in the middle of the driving lane, and drivers were instructed to avoid them. Participants were also instructed to report information on road signs disseminated around the circuit.
Drivers with glaucoma had a poorer overall driving score than the control group and hit significantly more hazards, suggesting poorer hazard detection ability. They also had larger saccades, while sign recognition and head movements did not differ significantly. Interestingly, larger saccades were associated with overall better driving performance in the glaucoma group.
“The drivers with glaucomatous visual impairment may need to scan the real-world driving environment more thoroughly to compensate for their visual loss,” the authors noted.
This study shows that visual field defects in individuals with glaucoma may be significant enough to interfere with their driving ability. However, in most cases they still legally fulfill Australian visual field requirements for an unconditional private driver’s license.
The authors concluded that larger studies are needed to establish more appropriate cut-off values and stricter parameters for individuals with glaucoma. – by Michela Cimberle
Disclosure: None of the authors reported a relevant financial disclosure.