Pandemic Masking Did Not Alter Anti-VEGF Linked Endophthalmitis Rate

Scan of the Retina.
Ophthalmology office. Masked patient and doctor – Covid 19. Scan of the retina, an examination that allows you to precisely visualize the different parts of the eye. This imaging makes it possible to observe the retina in order to detect, for example, a retinal uplift with edema or a diabetic retinopathy. It is used to monitor wet AMD about every two months and complements the fundus to see if an injection of treatment is needed. OCT is also used to examine the optic nerve, and therefore screen for or monitor glaucoma. (Photo by: Pascal Bachelet/BSIP/Universal Images Group via Getty Images)
Universal masking of physicians and patients does not reduce the rate of endophthalmitis after anti-VEGF injections.

The rate of endophthalmitis after anti-vascular endothelial growth factor (anti-VEGF) injections was already appreciably low before the COVID-19 pandemic; but the universal masking protocols that began in the spring months of 2020 offered an opportunity to establish whether masks could significantly affect bacterial transmission during the procedure.1 While the efforts have helped limit viral transmission of the SARS-CoV-2 virus, a large study published in Ophthalmology suggests that endophthalmitis rates remain unchanged.1,2

Investigators examined data from 4,206,234 anti-VEGF injections cataloged in the Intelligent Research in Sight (IRIS) Registry database to calculate rates of acute-onset endophthalmitis before and during the pandemic.

This study included figures for the 21-day period after intravitreal injections, with sets of data from April to June in years 2017 to 2020. It excluded patients younger than 18, those who had additional recent ocular procedures, and individuals with previous uveitis or panuveitis diagnoses. Participants had longer than 3 months of follow-up. “The rates of endophthalmitis were similar across the years: 0.0334% in 2017, 0.0324% in 2018, 0.0292% in 2019, and 0.0303% in 2020,” according to the report.1

This data is consistent with prior investigations that found little difference before and during the pandemic for overall rate of endophthalmitis after anti-VEGF or other types of intravitreal injections. A 12-center analysis by the Post-Injection Endophthalmitis Study Group scrutinized 505,968 injections administered between October 1, 2019 and July 31, 2020.3 Comparing unmasked patients and physicians with masked patient, doctor, and ancillary staff, the endophthalmitis rates for oral-flora-associated infection were relatively the same (P =.645).

Another investigation compared surgical masks, surgical masks secured with tape at the superior edge, N95s, cloth masks, and no face covering.4 Participants wearing untaped tight-fitting surgical masks produced the most bacterial colony-forming units (CFUs) on a forehead-positioned blood agar plate, both when silent or reading a 2-minute script. Conversely, taped tight-fitting surgical masks and N95s released the least bacterial colonies in the silent condition, and N95s grew the least number of CFUs when the patient spoke. In the silent scenario, those wearing cloth masks developed comparable numbers of CFUs as those unmasked (P =.831).4 

The current analysis did not differentiate cases based on whether the infection was confirmed with culture, which represents a limitation, as well as adjust for possible mask-wearing before the pandemic and validate definitive masking practices after its start.1 Further, the database does not include injections given at practices not affiliated with IRIS Registry.

AAO’s IRIS Registry is “the largest single-specialty electronic health record clinical data registry,” investigators explain.1 In July 2021, this database comprised more than 69 million individuals visiting participating clinics on over 397 million occasions, and provides information on uncommon adverse events and rare conditions. Investigators note that a geographically distributed database of this size can show trends inexpensively and quickly.

Disclosures: The study was supported by the Bruce E. Spivey MD Fund for Risk Management Studies, Ophthalmic Mutual Insurance Company, Foundation of the American Academy of Ophthalmology. 


1. Lum F, Li S, Liu L, et al. The pandemic not associated with endophthalmitis decrease after anti-VEGF injections. Ophthalmology. Published online January 15, 2022.

2. Brooks J, Butler J. Effectiveness of mask wearing to control community spread of SARS-CoV-2. JAMA. 2021;325(10):998-999. doi:10.1001/jama.2021.1505

3. Patel SN, Tang PH, Storey PP, et al, on behalf of the Post-Injection Endophthalmitis Study Group. The influence of universal face mask use on endophthalmitis risk after intravitreal anti-vascular endothelial growth factor injections. Ophthalmology. 2021;128(11):1620–1626.

4. Patel SN, Mahmoudzadeh R, Salabati M, et al. Bacterial dispersion associated with various patient face mask designs during simulated intravitreal injections.  Am J Ophthalmol. 2021;223(3):178-183. doi:10.1016/j.ajo.2020.10.017