Author Block: Jeff Park¹, Marko M. Popovic², Ravin Alaei³, Sherif R. El-Defrawy², Peter J. Kertes².

Disclosure Block: J. Park: None. M.M. Popovic: None. R. Alaei: None. S.R. El-Defrawy: None. P.J. Kertes: Membership on advisory boards or speakers’ bureaus; Name of for-profit or not-for-profit organization(s); Novartis, Roche, Bayer. All other investments or relationships that could be seen by a reasonable, well-informed participant as having the potential to influence the content of the educational activity; Name of for-profit or not-for-profit organization(s); Financial support (to institution) - Allergan, Bayer, Roche, Novartis; Financial support - Novartis, Bayer; Equity owner - ArcticDx.

Purpose: Intraocular transmission of exogenous pathogens in cataract surgery can lead to devastating consequences such as endophthalmitis. The aim of this study is to systematically evaluate the clinical features of infections that arise from pathogen transmission in cataract surgery, specifically with respect to the reported routes of transmission, etiologies and practical strategies to mitigate the associated risk.
Study Design: Systematic review.
Methods: A search strategy was employed using Ovid MEDLINE, EMBASE, and Cochrane CENTRAL (January 1990 to July 2020) to identify all articles reporting on endophthalmitis clusters following cataract surgery. All original studies with at least five patients that developed endophthalmitis from pathogen transmission during cataract surgery were included. The confirmed or suspected etiology and clinical features of endophthalmitis were recorded and presented. As well, collected variables included sample microbiology, plausible route of transmission, pathogen isolated from suspected source and recommendations for prevention of pathogen transmission. Risk of bias assessment was performed using a modified observational study risk of bias tool and quality of evidence was evaluated using the GRADE criteria.
Results: Following this review of 4418 identified articles, ten articles met the inclusion criteria and were considered for this review. Ninety-six patients from ten studies across eight countries were included. The phacoemulsification set (i.e. handpiece, tubing, and cassette) was the most commonly involved source of transmission identified in five studies, followed by fluid solutions identified in two studies. Nine studies reported on microbiological growth from patient ocular specimens, while four of the nine studies isolated the same pathogen from the suspected source of transmission. Patients with diabetes demonstrated worse visual outcomes following endophthalmitis in four of five studies included. Practical strategies to minimize risk of transmission and optimize pathogen detection included cleaning hollow instruments immediately after use, using molecular techniques to detect pathogens, refraining from reusing surgical materials, implementing environmental control strategies for the operating room, and instituting a governance strategy to oversee transmission risk. All included studies were assessed to have low risk of overall bias, but quality assessment revealed that clinical outcomes were of low to medium quality secondary to significant inconsistencies across studies.
Conclusions: Pathogen transmission during cataract surgery may occur via various routes and requires novel strategies for diagnosis, prevention and management. Recommendations from multiple domains of transmission risk prevention should inform future guidelines and comprehensive strategies for the prevention of endophthalmitis secondary to exogenous pathogen transmission.