Each year, traffic crashes account for 1.2 million deaths worldwide. Drivers 65 years and older have the highest death rate per mile driven, in part due to accidents caused by the most common reason for impaired vision: cataracts.

A recent study found that the rate of serious traffic crashes decreased by 9% from 2.36 per 1,000 patient-years in the baseline interval to 2.14 per 1,000 patient-years after cataract surgery.

Researchers evaluated 559,546 subjects who had cataract surgery in at least one eye. They recorded 4,680 crashes during the 3.5-year baseline interval and 1,200 during the 1-year subsequent interval.

“This study suggests that cataract surgery is associated with a modest decrease in a patient’s subsequent risk of a serious traffic crash as a driver,” the study authors said, “which has potential implications for mortality, morbidity and costs to society.”