Recent trends and outcomes in immediate and delayed sequential bilateral cataract surgeries: a nationwide cohort study in South Korea.

Purpose: To analyze the latest annual trends in immediate sequential bilateral cataract surgery (ISBCS) and delayed sequential bilateral cataract surgery (DSBCS) among patients with bilateral cataracts in Korea, and to identify the factors influencing the choice of surgery and the outcomes associated with ISBCS and DSBCS.

Methods: This retrospective, nationwide cohort study included all patients aged 65 and older who were covered by the Korean National Health Insurance and underwent ISBCS or DSBCS from 2016 to 2021. The study recorded yearly numbers of ISBCS and DSBCS procedures, the interval between surgeries in DSBCS cases, patient demographics, types of implanted intraocular lenses (IOLs), and the incidence of cystoid macular edema and endophthalmitis following ISBCS or DSBCS.

Results: A total of 50 878 (7.2%) patients underwent ISBCS, and 658 609 (92.8%) patients underwent DSBCS. ISBCS cases more than doubled in 2020 (7902) from 2019 (3703) before increasing even more significantly in number in 2021 (33 645). Age, hospital size, ocular and systemic comorbidities, type of IOL, and calendar year were associated with receiving ISBCS. In 2020 alone, the incidence of postoperative endophthalmitis among ISBCS patients was significantly higher (1.39 per 1000 procedures) than among DSBCS patients (0.40 per 1000 procedures; P = 0.001).

Conclusion: The number of patients undergoing ISBCS for bilateral cataracts increased annually, particularly after the onset of the COVID-19 pandemic in Korea in 2020. However, this significant rise in ISBCS also led to a surge in the incidence of postoperative endophthalmitis in 2020.