Association of Cataract Surgery With Traffic Crashes.

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.