Go to content

Cataract surgery helps reduce serious traffic crashes


Having cataract surgery reduces a patient’s subsequent risk of a traffic crash as a driver, according to a new study by researchers at the Institute for Clinical Evaluative Sciences (ICES).

“Our findings are important because the safety gains after cataract surgery are substantial and equal the benefits of an airbag,” says the study’s co-author Dr. Donald Redelmeier, who is a senior scientist at ICES, a staff physician at Sunnybrook Health Sciences Centre, and a professor at the Department of Medicine in the University of Toronto.

Cataract is a medical condition in which the lens of the eye becomes progressively opaque, resulting in blurred vision, decreased contrast, and increased glare. Cataract is the leading cause of impaired vision worldwide. 

Published today in the journal JAMA Ophthalmology, the researchers found a nine per cent reduction in the risk of a serious traffic crash in the year after cataract surgery compared to the years before cataract surgery.

The 10-year study included 559,546 patients who had cataract surgery from 2006 to 2016 and tracked 6,482 serious traffic crashes as drivers. Serious traffic crashes were defined as incidents that sent the driver to hospital for emergency care. The researchers found the crash rate decreased from 2.36 per 1,000 patient-years before surgery to 2.14 per 1000 patient-years after surgery. The absolute reduction was 0.22 per 1,000 patient-years equal to a number needed to treat of 4,564 to avoid one serious traffic crash in one year.

“The reduction in car crashes represents a significant societal benefit associated with cataract surgery,” says Dr. Matthew Schlenker, co-author on the study, surgeon scientist  at The Institute for Better Health, Trillium Health Partners, ophthalmologist at The Kensington Eye Institute, University Health Network, member of the Eye Physicians and Surgeons of Ontario, and assistant professor in the Department of Ophthalmology & Vision Sciences at the University of Toronto.

The researchers found the safety gains following cataract surgery were greatest among older women driving in rural regions. In contrast, the researchers found no safety gains for passengers, pedestrians, or other common forms of injury.

“It is important to note that patients with a past history of a traffic crash are particularly prone to a future traffic crash regardless of surgery,” adds Redelmeier.

Author block: Matthew B. Schlenker, Deva Thiruchelvam and Donald A. Redelmeier.

The article “Association of cataract surgery with traffic crashes” was published in the June 28 issue of the JAMA Ophthalmology.

The Institute for Clinical Evaluative Sciences (ICES) is an independent, non-profit organization that uses population-based health information to produce knowledge on a broad range of healthcare issues. Our unbiased evidence provides measures of health system performance, a clearer understanding of the shifting healthcare needs of Ontarians, and a stimulus for discussion of practical solutions to optimize scarce resources. ICES knowledge is highly regarded in Canada and abroad, and is widely used by government, hospitals, planners, and practitioners to make decisions about care delivery and to develop policy. For the latest ICES news, follow us on Twitter: @ICESOntario

For more information, please contact:

Deborah Creatura
Media Advisor, ICES
[email protected]
(o) 416-480-4780 or (c) 647-406-5996


Contributing ICES Scientists

Associated Sites

Read the Journal Article