Is glaucoma increasing road traffic accident rates?

by Gary Finnegan – World Health Matters (Japan) – Researchers in Japan have called for mandatory visual field testing for drivers in light of evidence showing glaucoma may increase the risk of road traffic accidents.

A new study conducted at the Tohoku University Graduate School of Medicine, in Sendai, Japan, found that divers with advanced glaucoma – a disease affecting peripheral vision – have twice as many accidents.

The study, presented at a joint meeting of the Asia-Pacific Academy of Ophthalmology and the American Academy of Ophthalmology, was conducted using a driving simulator. Two groups of 36 participants – one group with advanced glaucoma, the other with normal vision – were tested under a serious of controlled scenarios.

The most common accident for both the glaucoma and the normal-vision group was when a child, a car or another object suddenly entered the driver’s path from the side. The glaucoma group, however, had more than twice as many collisions as the normal-vision group.

Glaucoma is the second leading cause of blindness worldwide. If untreated, glaucoma reduces peripheral vision and eventually causes blindness by damaging the optic nerve. Because the disease is painless and vision loss is very gradual, only half of the people who have glaucoma are aware of it.

Prevalence of the disease rises with age making it a growing concern for countries with ageing populations such as Japan and several European nations. Rules governing the granting and renewal of driving licenses vary from country to country, with some – but not all – governments requiring drivers to pass visual field tests. In the US, a number of states insist that drivers with poor visual field scores install additional mirrors on their vehicles.

“To help ensure everyone’s safety on our roadways, we would like to create mandatory vision testing guidelines for glaucoma patients,” said Dr Shiho Kunimatsu-Sanuki, lead researcher on the study. “We now know that integrating the visual field test into the requirements for a driver’s license could save lives.”

With proper medical care, many people with glaucoma can maintain a level of vision that would enable safe driving. The American Academy of Ophthalmology said it recommends that everyone have a complete eye exam at age 40 so that glaucoma and other age-related eye diseases can be diagnosed and treated early to minimise vision loss.