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Association of Cataract Surgery With Traffic Crashes

Educational Objective
To conduct a comprehensive longitudinal analysis testing whether cataract surgery is associated with a reduction in serious traffic crashes where the patient was the driver.
1 Credit CME
Key Points

Question  Is cataract surgery associated with reduced serious traffic crashes as a driver?

Findings  In this population-based, study of 559 546 patients who received at least 1 eye cataract surgery, the crash rate decreased from 2.36 per 1000 patient-years in the baseline interval to 2.14 per 1000 patient-years after surgery, representing a 9% reduction in serious traffic crashes.

Meaning  These results suggest cataract surgery is associated with a patient’s reduced subsequent risk of serious traffic crash as a driver.


Importance  Cataracts are the most common cause of impaired vision worldwide and may increase a driver’s risk of a serious traffic crash. The potential benefits of cataract surgery for reducing a patient’s subsequent risk of traffic crash are uncertain.

Objective  To conduct a comprehensive longitudinal analysis testing whether cataract surgery is associated with a reduction in serious traffic crashes where the patient was the driver.

Design, Setting, and Participants  Population-based individual-patient self-matching exposure-crossover design in Ontario, Canada, between April 1, 2006, and March 31, 2016. Consecutive patients 65 years and older undergoing cataract surgery (n = 559 546).

Interventions  First eye cataract extraction surgery (most patients received second eye soon after).

Main Outcomes and Measures  Emergency department visit for a traffic crash as a driver.

Results  Of the 559 546 patients, mean (SD) age was 76 (6) years, 58% were women (n = 326 065), and 86% lived in a city (n = 481 847). A total of 4680 traffic crashes (2.36 per 1000 patient-years) accrued during the 3.5-year baseline interval and 1200 traffic crashes (2.14 per 1000 patient-years) during the 1-year subsequent interval, representing 0.22 fewer crashes per 1000 patient-years following cataract surgery (odds ratio [OR], 0.91; 95% CI, 0.84-0.97; P = .004). The relative reduction included patients with diverse characteristics. No significant reduction was observed in other outcomes, such as traffic crashes where the patient was a passenger (OR, 1.03; 95% CI, 0.96-1.12) or pedestrian (OR, 1.02; 95% CI, 0.88-1.17), nor in other unrelated serious medical emergencies. Patients with younger age (OR, 1.27; 95% CI, 1.13-1.14), male sex (OR, 1.64; 95% CI, 1.46-1.85), a history of crash (baseline OR, 2.79; 95% CI, 1.94-4.02; induction OR, 4.26; 95% CI, 2.01-9.03), more emergency visits (OR, 1.34; 95% CI, 1.19-1.52), and frequent outpatient physician visits (OR, 1.17; 95% CI, 1.01-1.36) had higher risk of subsequent traffic crashes (multivariable model).

Conclusions and Relevance  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, which has potential implications for mortality, morbidity, and costs to society.

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Article Information

Corresponding Author: Matthew B. Schlenker, MD, MSc, FRCSC, Kensington Eye Institute, 340 College St, Ste 400, Toronto, ON M5T 3A9, Canada (

Accepted for Publication: May 4, 2018.

Published Online: June 28, 2018. doi:10.1001/jamaophthalmol.2018.2510

Author Contributions: Drs Redelmeier and Thiruchelvam had full access to all the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis.

Concept and design: Schlenker, Redelmeier.

Acquisition, analysis, or interpretation of data: All authors.

Drafting of the manuscript: Schlenker.

Critical revision of the manuscript for important intellectual content: All authors.

Statistical analysis: All authors.

Supervision: Redelmeier.

Conflict of Interest Disclosures: All authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest and none were reported.

Funding/Support: Dr Redelmeier is supported by a Canada Research Chair.

Role of the Funder/Sponsor: The funding source had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.

Additional Contributions: We thank the following for helpful comments: Michael Fralick, MD, MSc, FRCPC, St Michael’s Hospital, University of Toronto; Husayn Gulamhusein MD, MPH, Department of Ophthalmology, McMaster University; Ann Lvin, COMT, MSc, Kensington Vision and Research Centre; Marko Popovic, MD(C), University of Toronto; Sheharyar Raza, MD(C), University of Toronto; Jay Udell, MD, MPH, FRCPC, Women’s College Research Institute, Institute for Clinical Evaluative Sciences, University Health Network, University of Toronto; and Jason Woodfine, MD, Department of Internal Medicine, University of Ottawa. No compensation was received from a funding sponsor for these contributions.

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