Contents lists available at ScienceDirect Progress in Retinal and Eye Research journal homepage: www.elsevier.com/locate/preteyeres Critical analysis of techniques and materials used in devices, syringes, and needles used for intravitreal injections Gustavo Barreto Melo a,b,*,1 , Natasha Ferreira Santos da Cruz b,1 , Geoffrey Guy Emerson c,1 , Flávio Atanázio Rezende d,1 , Carsten H. Meyer b,e,1 , Susumu Uchiyama f,1 , John Carpenter g,1 , Hélio Francisco Shiroma b,1 , Michel Eid Farah b,1 , Maurício Maia b,1 , Eduardo Büchele Rodrigues b,h,1 a Hospital de Olhos de Sergipe, Rua Campo do Brito, 995, Aracaju, SE, Brazil b Department of Ophthalmology, Federal University of São Paulo, Rua Botucatu, 806, São Paulo, SP, Brazil c Retina Center of Minnesota, 710 E 24th Street, Suite #304, Minneapolis, MN, USA d Maisonneuve-Rosemont Hospital, University of Montreal, Montreal, Quebec H1T 2M4, Canada e Department of Ophthalmology, Philipps University of Marburg, Robert-Koch-Strasse 4, Marburg, Germany f Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Osaka, Japan g Department of Pharmaceutical Sciences, University of Colorado, Denver/Aurora, CO, USA h Department of Ophthalmology, SSM Health Saint Louis University Hospital, Saint Louis University, 1755, S. Grand Boulevard, Saint Louis, MO, USA ARTICLE INFO Keywords: Anesthesia Device Intravitreal injection Needle Silicone oil Syringe ABSTRACT Intravitreal injections have become the most commonly performed intraocular treatments worldwide. Because intravitreal injections may induce severe adverse events, such as infectious and noninfectious endophthalmitis, cataract, ocular hypertension, vitreous hemorrhage, or retinal detachment, appropriate awareness of the ma- terials and techniques used are essential to reduce these sight-threatening complications. This review provides insights into the needles, syringes, silicone oil coating, sterilization methods, devices to assist intravitreal in- jections, scleral piercing techniques using needles, syringe handling, anesthesia, and safety issues related to materials and techniques. It is paramount that physicians be aware of every step involved in intravitreal in- jections and consider the roles and implications of all materials and techniques used. The ability to understand the theoretical and practical circumstances may definitely lead to state-of-the-art treatments delivered to pa- tients. The most important practical recommendations are: choosing syringes with as little silicone oil as pos- sible, or, preferably, none; avoiding agitation of syringes; awareness that most biologics (e.g., antiangiogenic proteins) are susceptible to changes in molecular properties under some conditions, such as agitation and temperature variation; understanding that improper materials and techniques may lead to complications after intravitreal injections, e.g., inflammation; and recognizing that some devices may contribute to an enhanced, safer, and faster intravitreal injection technique. 1. Introduction Intravitreal injections (IVIs) have been used to manage human ocular diseases for more than a century. In 1911, an IVI was used to introduce air inside the intraocular space to repair retinal detachments. In the 1940s, experiments with IVIs of antibiotics, especially penicillin, for endophthalmitis were reported (Kelly, 1948; Leopold, 1945; Maurice, 1979). The United States Food and Drug Administration formally approved fomivirsen (Vitravene, Novartis, Basel, Switzerland) for intraocular use in 1998 (Doshi et al., 2011a). However, since it is an antiviral for a very specific indication, it never achieved widespread use. Until 2004, IVIs of antibiotics were usually administered off-label to treat infectious endophthalmitis, IVIs of corticosteroids for inflammatory conditions and macular edema, and IVIs of gas tamponades for pneumatic re- tinopexy (Lad and Moshfeghi, 2006). Between 2000 and 2002, about 4500 IVIs were performed yearly in the United States (Avery et al., 2014; Williams, 2014). The numbers of https://doi.org/10.1016/j.preteyeres.2020.100862 Received 24 January 2020; Received in revised form 23 March 2020; Accepted 2 April 2020 * Corresponding author. Hospital de Olhos de Sergipe, Rua Campo do Brito, 995 49020-380, Aracaju, SE, Brazil. E-mail address: gustavobmelo@yahoo.com.br (G.B. Melo). 1 Percentage of work contributed by each author in the production of the manuscript is as follows: G.B. Melo: 40%; N.F.S. da Cruz: 5%; G.G. Emerson: 5%; F.A. Rezende: 5%; C.H. Meyer: 5%; S. Uchiyama: 5%; J. Carpenter: 5%; H. F. Shiroma: 5%; M.E. Farah: 5%; M. Maia: 5%; E.B. Rodrigues: 15%. Progress in Retinal and Eye Research xxx (xxxx) xxxx 1350-9462/ © 2020 Elsevier Ltd. All rights reserved. Please cite this article as: Gustavo Barreto Melo, et al., Progress in Retinal and Eye Research, https://doi.org/10.1016/j.preteyeres.2020.100862