Visual outcomes of cataract surgery in the United States, Canada, Denmark, and Spain: Report from the International Cataract Surgery Outcomes Study

Objective: To compare visual outcomes obtained following cataract surgery in 4 sites in North America and Europe where considerable differences in the organization of care and patterns of clinical practice have been previously described. Methods: Patients scheduled for first eye-cataract surgery and aged 50 years or older were enrolled consecutively in a prospective multicenter study that collected clinical and patient interview data preoperatively and postoperatively. From the United States, 772 patients were enrolled; from the Province of Manitoba (Canada), 159; from Denmark, 291; and from the City of Barcelona (Spain), 200. Preoperative and 4-month postoperative visual acuity was obtained for 92% of the patients (n = 1291). Results: The mean 4-month postoperative visual acuity of eyes operated on varied significantly across the 4 sites (P < .001) and had the following Snellen decimal fraction measurements: 0.49 in Barcelona, 0.65 in Denmark, 0.66 in Manitoba, and 0.74 in the United States. However, while crude visual acuity outcome figures varied significantly, no significant difference was observed across the 4 sites regarding the risk of poorer visual outcome after controlling for differences in age, preoperative visual acuity, and general health status for patients with no ocular comorbidity. Older age, poorer preoperative visual acuity, poorer preoperative general health status, and coexisting ocular comorbidity were predictors of a poorer visual outcome. Conclusion: A previously identified variation in treatment modalities across the 4 sites did not seem to affect patients' visual acuity outcomes.