Incidence of Acute Post-cataract Surgery Endophthalmitis in Two Major Referral Centers in Iran and the Prophylactic Effect of Perioperative Vancomycin: An Observational Retrospective Study

Abstract

Background: Cataract surgery is among the most prevalent operations and one of the most successful interventions in medicine globally. Endophthalmitis is the most important complication of this surgery, which, despite its low incidence, is a major concern for surgeons due to subsequent visual consequences. Objectives: To investigate the epidemiological incidence of post-cataract surgery endophthalmitis in two major ophthalmology referral centers in Iran, and the impact of perioperative vancomycin as a prophylactic option. Methods: This retrospective cohort study included patients who underwent the phacoemulsification cataract surgery procedure over January 2017 to January 2024 at two referral centers: Imam Khomeini Hospital in Kermanshah, Kermanshah, Iran (group A) and Nikookari Hospital in Tabriz, East Azerbaijan, Iran (group B). All patients who underwent cataract surgery using the phacoemulsification technique were included in the study through a census method. Patients who underwent cataract surgery by methods other than phacoemulsification, including extra-capsular cataract extraction (ECCE), intra-capsular cataract extraction (ICCE), and pars plana lensectomy, age under 18 years, and traumatic cataract were exclusion criteria. The data were analyzed by SPSS-25 utilizing descriptive statistics (frequency and percentage) as well as inferential statistical tests, including Fisher's exact test, chi-square test, and independent t-test. Results: This study examined 54,071 phaco cataract surgeries, of which 71 patients developed endophthalmitis (0.131%). This research included 20,444 surgeries performed in Imam Khomeini Ophthalmology Center without vancomycin in the irrigating serum (group A) and 33,627 surgeries performed in Nikookari Eye Center with vancomycin in balanced salt solution (BSS, group B). Fifty-two cases of acute post-cataract surgery endophthalmitis were identified in group A, resulting in an incidence of 0.254%, in contrast, 19 cases occurred in group B, with an incidence of 0.056%. The incidence of endophthalmitis was significantly lower in the vancomycin-exposed group compared to the non-exposed group, and vancomycin reduced incidence by 0.061% (0.154% vs. 0.092%, ARR: 0.061%, P = 0.02). The two groups were similar regarding age (P = 0.97), gender distribution (P = 0.75), intraoperative complications (P = 0.50), and other predisposing factors. Conclusions: This study shows promising preventive effects of perioperative vancomycin in irrigating serum on post-cataract surgery endophthalmitis occurrence.