Intravitreal Injections and Endophthalmitis

Stephen J. Kim, MD


Int Ophthalmol Clin. 2015;55(2):1-10. 

In This Article


Although there are several methods used for anesthesia, there are no consensus recommendations regarding optimal method to reduce risk of infection. Previous studies have shown that lidocaine possesses broad inhibitory effects against gram-positive, gram-negative, mycobacteria, and fungal organisms. In addition, similar to povidone-iodine, its nonselective mechanism of action makes it less susceptible to resistance. An in vitro study demonstrated that 2% lidocaine possesses rapid bactericidal effects against S. epidermidis, S. aureus, and S. viridans.[28] This strong inherent propensity for lidocaine to eradicate bacteria may have useful practical applications when performing IVT injections.

Subconjunctival anesthesia is a well described, effective, and commonly used method. A retrospective study reported no cases of endophthalmitis of 6853 IVT injections performed with subconjunctival lidocaine and 8 cases of endophthalmitis of 8189 IVT injections performed with other methods of anesthesia (P=0.03).[28] Subconjunctival lidocaine may allow for optimal contact of povidone-iodine to the ocular surface in comparison with more viscous formulations of topical lidocaine. Furthermore, independent of its antibacterial properties, subconjunctival lidocaine may serve to wash away or dilute pathogens adhering to the injection needle as it passes through the fluid medium of the raised bleb and by similar mechanisms retard entry of pathogens from the ocular surface through a wound track.