Endophthalmitis Rates following Secondary Intraocular Lens Surgeries: An 11-year Medicare Fee-For-Service Analysis.

Purpose: To assess postoperative endophthalmitis (POE) rates and risk factors after secondary intraocular lens (IOL) implantation for preoperative aphakia and IOL exchange combined with or without vitrectomy.

Setting: Medicare fee for service (FFS) beneficiaries, United States.

Design: Retrospective study.

Methods: Medicare FFS beneficiaries who underwent IOL exchange or secondary IOL implantation for preoperative aphakia between January 1, 2011 - November 19, 2022 were identified. POE rates were calculated overall and separately for each surgical category - secondary IOL for aphakia versus IOL exchange, with subsets for concurrent anterior or posterior vitrectomy. Multi-variate analysis of potential risk factors was implemented.

Results: 97,152 patients were included. The 42-day POE rates for secondary IOL implantation for aphakia and for IOL exchange were 0.35% and 0.28% overall, 0.31% and 0.30% when combined with posterior vitrectomy, and 0.84% and 0.42% with anterior vitrectomy. The risk of POE increased when secondary IOL surgery was combined with anterior vitrectomy compared to no vitrectomy (adjusted odds ratio [aOR] 1.849; p<0.001) and with higher Charlson comorbidity indexes compared to 0: 1-2 (aOR 1.495; p=0.01), 3-4 (aOR 1.591; p=0.01), 5-6 (aOR 1.617; p=0.046), ≥7 (aOR 3.290; p<0.001). Risk was decreased for IOL exchange compared to secondary IOL implantation for preoperative aphakia (aOR 0.783; p=0.04).

Conclusion: The overall POE rate for all secondary IOL surgeries was 0.31% during the 11-year period. We hypothesize that absence of the posterior capsular barrier would explain the higher POE rates compared with cataract surgery, especially if a concurrent vitrectomy was performed with the secondary IOL procedure.