Author Block: Amit V. Mishra  , C Maya Tong, Marvi Cheema, David Plemel, Uriel Rubin, Bo Bao, Samir Nazarali, Steven R. J. Lapere, Rizwan Somani, Bradley Hinz, Matthew T. S. Tennant.  ¹

Author Disclosure Block: A.V. Mishra:   None.  C. Tong:   None.  M. Cheema:   None.  D. Plemel:   None.  U. Rubin:   None.  B. Bao:   None.  S. Nazarali:   None.  S.R.J. Lapere:   None.  R. Somani:   None.  B. Hinz:   None.  M.T.S. Tennant:   None.

Abstract Title: Comparison of endophthalmitis rates following alcohol-based chlorhexidine and povidone-iodine antisepsis for intravitreal anti VEGF injections

Abstract Body: Purpose:   Intravitreal injections (IVI) are the most frequently performed intraocular procedure in Canada. Povidone-iodine (PI) is the current gold standard for antisepsis for IVI and is widely used; chlorhexidine (CH) is an alternative antiseptic agent. This study aims to compare rates of endophthalmitis after IVI with 0.05% chlorhexidine with 4% alcohol base antisepsis to rates of endophthalmitis after IVI with povidone-iodine antisepsis.   Study Design:   Retrospective cohort study.   Methods:   Eyes at a single center received either 10% PI antisepsis or 0.05% CH in 4% antisepsis before each IVI at a single retina clinic. Cases of endophthalmitis were identified and incidences per antiseptic agent were calculated. Chi square test and odds ratio were performed.   Results:   A total of 135832 IVIs were performed during the study. There were a total of 49 cases of endophthalmitis. There were 20 cases of endophthalmitis in the CH group (0.089%) while the PI group had 29 (0.026%). There was a statistical difference in the number of endophthalmitis cases per antiseptic (p = 4.48e-06). There was an increased odds (3.49) of developing endophthalmitis with CH antisepsis compared to PI.   Conclusions:   There is a higher rate of endophthalmitis when using CH antisepsis compared to PI. Overall the rates in the two groups were within the reported incidences in the literature. We recommend CH be used only as a second line agent for those patients intolerant of PI. Patients should be made aware of the increased risk of endophthalmitis associated with CH antisepsis.