Simulation reveals impact of poor vision on driving

Eyesight is a key factor in safe driving yet is often overlooked as new analysis from Direct Line Car Insurance reveals that the equivalent of nearly a person a day (345) is injured in a crash involving a driver with uncorrected or defective eyesightand 64 people were killed or seriously injured in 2015 alone.

Direct Line analysed the effects of impaired vision on driving performance at TRL’s advanced driving simulator (Digicar) completing five drives, each with different levels of vision. The drives took place on TRL’s ‘impairment route’, which is a specially constructed motorway environment, designed to measure safety-critical driving performance, including vehicle following, traffic navigation, curve following and reaction times.

The results indicated that when vision falls below the legal limit there are serious implications on driving performance; it is harder to stay in lane and to keep a consistent speed and a safe distance between the car in front. Poor eyesight also impedes the driver’s ability to react to unexpected hazards, resulting in sudden braking and an increased risk of causing or being involved in an accident.

A staggering 13.3 million motorists admit to needing glasses or contact lenses to drive but never wears them, meaning one in five (21 per cent) drivers are regularly putting their lives and those of other road users at risk. This is despite good eyesight not only being a prerequisite for safe driving, but a legal requirement.

Furthermore, 16 per cent of all drivers have had an accident in the last two years but this figure rockets to 67 per cent for those who don’t wear their glasses or contact lenses when driving, increasing their chance of an accident fourfold.

Changes to vision can occur slowly, often to the point where the driver themselves may not realise that their vision is changing. This could be general deterioration in a person’s eyesight or a more serious condition like macular degeneration, cataracts or glaucoma, which can lead to blindness. This is extremely concerning as more than a third (37 per cent) of motorists claim they have not had a vision test in the past two years or more.

Gus Park, director of motor at Direct Line commented: “This research shows just how dangerous it can be to drive without good or corrected eyesight, especially at this time of year when the clocks go back, as conditions such as Glaucoma and Cataracts can make it harder to drive in the dark. 

Park continues: “The current driving eyesight check is a moment in time and, for many drivers, the only sight test they have had in over twenty years. You wouldn’t expect the pilot flying you home or the train or bus driver on your daily commute to have poor eyesight. We would encourage a review into the current requirements for vision testing in relation to driving to ensure the safety of all road users".

Motorists who drive without glasses or contact lenses4 risk invalidating their insurance, receiving a fine and in some cases, imprisonment. The only way a driver can be completely certain that they remain both legal and safe is to have regular eye examinations. If a driver’s eyesight is below decimal 0.5 (6/12) measured on the Snellen scale, or they have an eye condition such as cataracts or glaucoma, they will have to inform the DVLA. Drivers must also be able to read a car number plate from 20 meters - if they are asked to read one and cannot, their licence may be revoked and they could be prosecuted.

Optometrist Henry Leonard, Clinical and Regulatory Officer at the Association of Optometrists (AOP) said: “In the UK there is currently no requirement for drivers to have regular sight tests. This means that a 17-year-old, who can read a number plate when they take their driving test, may continue driving for the rest of their life with no further vision checks. Roadside tests have shown that many drivers subsequently fall below the required standard as their eyesight changes over time, often without realising.”

“In much the same way that cars are required to have an MOT to ensure they are roadworthy, we believe that regular sight testing should be compulsory for all motorists, to ensure that their vision meets the required standards. A sight test also includes an eye health check, and might even detect signs of underlying general health conditions, such as diabetes, high cholesterol and high blood pressure.”