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• Posted November 10, 2023

How Much Vision Loss Impairs Your Driving? New Study Has Answers

A Mr. Magoo with thick glasses peering out from behind the wheel might not inspire confidence from his fellow motorists, but a new study shows other types of vision loss might be even more dangerous while driving.

Loss of peripheral vision also can dramatically increase the risk of a car crash, Australian researchers presented in findings this week at the American Academy of Ophthalmology's annual meeting in San Francisco. Such research is considered preliminary until published in a peer-reviewed journal.

Eye chart tests check for visual acuity, or the ability to see distant objects clearly, and state laws generally require motorists to have 20/40 vision or better in at least one eye to drive unrestricted.

But researchers instead focused on visual field, or how widely a person can see when staring straight ahead.

A wide field of vision would allow drivers to see potential hazards on either side of a car while still paying attention to what is in front of them.

The research team at Western Australia University evaluated nearly three decades' worth of data on more than 31,000 drivers aged 50 or older.

More than 4,000 of the older drivers (14%) had been involved in at least one car crash, and more than half of those were experiencing some extent of visual field loss.

Analysis showed that visual field loss of any sort in both eyes increased the risk of a car crash by 84%.

Severe vision loss in any quadrant of a person's visual field increased the chances of a crash, but loss of central vision in either eye did not increase accident risk, researchers found.

"Many people think that only good visual acuity or clarity of vision is necessary for safe driving,"said lead researcher Dr. Siobhan Manners, a research associate with Western Australia University.

"We hope these results will help educate the public about the importance of having an adequate field of vision to be able to continue driving safely,"Manners added in a meeting news release. "We also hope to better inform clinicians, licensing authorities and people with visual field defects of the thresholds for visual field loss that still allow for safe driving."

More information

The American Academy of Ophthalmology has more about vision and driving.

SOURCE: American Academy of Ophthalmology, news release, Nov. 6, 2023