7th November 2019
6 minute read
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Industry News

Cataracts and driving – cataract surgery linked to a reduced risk of car crashes

Cataract Surgery and Driving in Canada

A recent study looked at the relationship between cataracts and driving, and found that drivers with cataracts who undergo cataract removal surgery reduce their risk of getting into car crashes. Data on more than half a million Canadian seniors (76 years old on average) showed that traffic accident rates fell after drivers underwent cataract removal surgery.

Although a modest decline – around 9 percent – the research suggests that, “improvements in visual function from cataract surgery are associated with decreased driving risks,” according to the research team led by Dr Matthew Schlenker, of the Kensington Eye Institute in Toronto.

The Canadian team looked at the medical and driving records of more than 559,000 Ontario residents aged 65 and older between 2006 and 2016. The researchers found that traffic crash rates fell by an average of 9 percent in the year following a cataract surgery versus the 3.5 years before the procedure. This reduction was more pronounced – a 14 percent drop – among drivers over the age of 75.

Notably, cataract surgery had no effect on traffic accidents where the patient was a passenger or a pedestrian.

Overall, Schlenker’s team calculated that doctors would need to treat 4,564 patients to avoid one crash a year, researchers report in JAMA Opthalmology.

Dr Mark Fromer, an ophthalmologist at Lenox Hill Hospital in New York City, said the new study shows that “improved vision as a result of cataract surgery in the elderly population likely represents a significant reduction in economic societal costs, injuries and deaths related to traffic-related injuries.”

While the study couldn’t prove cause and effect, the results are not surprising. One eye doctor, independent of the study, said: “The most common cataracts symptoms are blurred vision, sensitivity to light, glare, dimness of vision, and difficulty seeing at night,” noted Dr Matthew Gorski, an ophthalmologist at Northwell Health in Great Neck, N.Y. All of those symptoms “can seriously impact a patient’s safety while driving…”

Gorski highlights that the study should remind older drivers that: “…it is important for any patient who notices a change in vision to have an eye exam with an eye doctor. This study reiterates the importance for all patients over the age of 40 to have a yearly routine eye exam.”

The focus on people who participated in traffic collisions serious enough to require emergency medical treatment offers high-quality evidence that cataract surgery may be one effective approach to reducing the risk of these incidents, said Dr Justine Smith, a researcher at Flinders University in Adelaide, Australia. “The investigators were able to associate cataract surgery with decreased risk of a serious traffic accident,” Smith added. “This tells you that if you or an elderly relative develop a cataract that affects the vision, one good reason to have the cataract operated, is for road use (car, motorbike or bicycle) safety.”

Not everybody with a cataract needs surgery, and not everyone with a cataract will have difficulty driving safely, noted Dr Kevin Miller of the Stein Eye Institute and the David Geffen School of Medicine at the University of California, Los Angeles.

“The difficulty comes with everybody in between where they have some cataract and it’s creating some effect on their vision but it’s not to the point where they can’t pass a driver’s vision test,” Miller said. “There are many, many people that fall into that grey zone.”

The findings were published online on June 28 in JAMA Ophthalmology.

Is there an even closer relationship between cataracts and car crashes?

Prior research highlights a more pronounced relationship between cataracts and driving. An earlier study by Owsley et al (1999), researched the driving habits of elderly (aged 55-85 years) participants with and without cataracts and found, compared to those without cataract, older drivers with cataract were approximately two times more likely to report reductions in days driven and number of destinations per week, driving slower than the general traffic flow, and preferring someone else to drive.

Additionally, those with cataract were five times more likely to have received advice about limiting their driving and were four times more likely to report difficulty with challenging driving situations. Participants reporting driving difficulty were two times more likely to reduce their driving exposure. Drivers with cataract were 2.5 times more likely to have a history of at-fault crash involvement in the prior 5 years (adjusted for miles driven/week and days driven/week). These associations remained even after adjustments for the confounding effects of advanced age, impaired general health, mental status deficit, or depression.

The researchers concluded that, “Older drivers with cataract experience a restriction in their driving mobility and a decrease in their safety on the road…”

Cataract Surgery and Driving in Australia

Research conducted by Dr Matthew Schlenker’s team between 2004-2006 in Canada was validated by a smaller study conducted by a group of scientists (Lynn B Meuleners, Kate Brameld, Michelle L Fraser and Kyle Chow) in Western Australia [2018].

Their study – albeit of a smaller group of 2,849 adults – looked at drivers aged 60 and over.

The results showed a 61% reduction in the number of car accidents once the cataract was removed from the first eye.

An additional 23% reduction in car accidents was linked to cataract removal in the second eye.

For those with cataracts in both eyes, although the biggest difference is from the first eye’s cataract removal. the authors emphasised that there’s still a significant reduction in risk of accidents associated with the cataract removal from the second eye.

“These results provide encouragement for the timely provision of first and second eye cataract surgery for older drivers,” the scientists concluded.

Cataract Surgery and Driving in the UK

These studies indicate that any vision loss will likely result in changes to driving style, a loss of confidence behind the wheel, and a small risk of an accident becoming “when” not “if”. It is important to continually monitor your eye health and report changes to the DVLA if necessary.

In 2018, the DVLA moved to update its cataracts guidance.

You can find out more about UK government vision standards for driving by clicking here.

For more information on cataract surgery click here.

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