Effect of the time interval between cataract surgery for both eyes on mental health outcome: a cohort study of 585,422 patients

Background: Cataract surgeries can improve mental health outcomes. However, previous studies have not investigated whether the time interval between cataract surgeries for 2 eyes affects mental health outcomes. Methods: We used the whole-population National Health Insurance (NHI) claims data from Taiwan to conduct a cohort study. Patients who received cataract surgeries for both eyes were identified (n = 585,422). The mental health inpatient and outpatient consultations received by these patients were analyzed, with different time intervals (< 3, 3 to 6, 6 to 12, and > 12 months) between the surgeries. Negative binominal regression was performed to estimate the interaction of the first eye surgery with the time interval. Results: The number of mental health consultations was lowest among patients with a time interval of < 3 months (1.783–1.743, P <.001), and a negative dose response effect was observed, such that a longer time interval corresponded to a lower reduction in the number of mental health consultations. For patients with a time interval of > 12 months, the predicted number of mental health consultations increased from 1.674 to 1.796 (P <.001). Conclusions: Given a patient expected to receive surgeries for both eyes within 1 year, scheduling both surgeries within a short time interval may be beneficial for maximizing the effects of cataract surgery in reducing the number of mental health consultations.