Practices vary in relation to the settings in which intravitreal injections are performed.  While in the past they were mainly performed in the operating room environment, more recently an increasing number of physicians prefer the office or a sterile room.  According to a survey performed in the UK ophthalmology units, 83% of intravitreal injections are performed in a dedicated clean room1, and a similar survey performed in Canada showed that the majority of intravitreal injections are now performed in an office setting2. The literature confirms that endophthalmitis rates are comparably low.  In a study3 including a total of 11,710 injections, 8,647 of which performed in an office-based setting and 3,063 in the OR, a total of 5 cases (0.043%) of suspected endophthalmitis occurred. Three cases (0.035%) occurred in the office-based group, and 2 cases (0.065%) occurred in OR group.  Another retrospective study including over 500,000 injections performed in an office-based setting in 5 retina practices in the US, reported 183 cases of endophthalmitis at a rate of 0.036%4.  Other studies show similar rates.  However, prospective, randomized trials are lacking and the choice of one or the other clinical setting largely depends on the laws and regulations applied in individual countries.

Anat Loewenstein, MD, MHA

Professor of Ophthalmology and Deputy Dean, Medical School, Sackler Faculty of Medicine, Tel Aviv University, and Chairman of the Department of Ophthalmology, Tel Aviv Sourasky Medical Center (TASMC, Tel Aviv, Israel)


Paolo Lanzetta, MD

Professor and Chair of the Department of Ophthalmology, University of Udine and Scientific Director of the European Institute of Ocular Microsurgery (IEMO), Udine, Italy.


Carl D. Regillo, MD, FACS

Director of the Retina Service, Wills Eye Hospital, Philadelphia, USA.

United States

Timothy Y.Y. Lai, MD, FRCS, FRCOphth

Honorary Clinical Associate Professor, Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong.

Hong Kong

Chiara M. Eandi, MD, PhD

Hôpital ophtalmique Jules-Gonin, Lausanne, Switzerland.


Louis R. Giavedoni, MD, FRCS(C)

St. Michael’s Hospital, Toronto, Canada.


Marc de Smet, MD, PhD

Professor and Head of MIOS, Lausanne, Switzerland. CMO of Preceyes.


Francesco Boscia, MD

Professor, University of Bari Aldo Moro, Italy.


Pavel Stodulka, PhD, FEBOS-CR

Gemini Eye Clinics, Zlín, Czechia and Wien, Austria.


Detlef Holland, MD

EyeClinic, Bellevue, Kiel, Germany


1 Samia-Aly E, Cassels-Brown A, Morris DS, Stancliffe R, Somner JE. A survey of UK practice patterns in the delivery of intravitreal injections. Ophthalmic Physiol Opt. 2015 Jul;35(4):450-4. doi: 10.1111/opo.12217.

2 Xing L, Dorrepaal SJ, Gale J: Survey of intravitreal injection techniques and treatment protocols among retina specialists in Canada. Can J Ophthalmol 2014; 49: 261–266.

3 Tabandeh H, Boscia F, Sborgia A, Ciracì L, Dayani P, Mariotti C, Furino C, Flynn HW Jr. Endophthalmitis associated with intravitreal injections: office-based setting and operating room setting.Retina. 2014 Jan;34(1):18-23. doi: 10.1097/IAE.0000000000000008.

4 Rayess N, Rahimy E, Storey P, Shah CP, Wolfe JD, Chen E, DeCroos FC, Garg SJ, Hsu J.Postinjection Endophthalmitis Rates and Characteristics Following Intravitreal Bevacizumab, Ranibizumab, and Aflibercept. Am J Ophthalmol. 2016 May;165:88-93. doi: 10.1016/j.ajo.2016.02.028.