Postoperative Corneal Injuries: Incidence and Risk Factors

Previous studies of postoperative corneal injury rates relied on provider-initiated incident reports, which may underestimate the true incidence. Postoperative administration of proparacaine eye drops is used almost exclusively to diagnose corneal injury; therefore, identifying instances of administration may provide a better estimate of corneal injuries. We compared proparacaine administration versus provider-initiated reports to determine rates of corneal injury. In addition, potential associations between clinical variables and injury were assessed with a matched case-control study.

The health records of 132,511 sequential adult postanesthesia recovery room admissions (January 1, 2011 to June 30, 2017) were reviewed to identify postoperative proparacaine administration and incident reports of corneal injury. Patients with corneal injury were matched with control patients at a 1:2 ratio to assess factors associated with injury.

Proparacaine drops were administered to 442 patients (425 patients received proparacaine for diagnosis and 17 patients received proparacaine for unrelated reasons). Incident reports identified 320 injuries, and the aggregate corneal injury count was 436 (incidence, 3.3 injuries [95% confidence interval {CI}, 3.0-3.6] per 1000 cases of general anesthesia). Proparacaine administration had a greater case ascertainment percentage than incident reporting (97.5% vs 73.4%; P < .001). The matched case-control analysis found greater risks associated with longer duration of anesthesia (odds ratio, 1.05 [95% CI, 1.03-1.07] per 10 minutes of anesthesia; P < .001) and nonsupine surgical position (odds ratio, 3.89 [95% CI, 2.17-6.98]; P < .001). Patients with injuries also had more evidence of sedation and agitation during anesthesia recovery.

Calculation of incidence by using the administration of a medication (proparacaine eye drops) that is almost exclusively used to diagnose a specific injury (corneal injury) showed higher case ascertainment percentage than incident-reporting methods. Similar strategies could be used to monitor the rates of other adverse events.