Evaluating The Rates Of Postintravitreal Injection–Related Endophthalmitis - COVID-19 & Physician - Patient Face Masking.

Evaluating The Rates Of Postintravitreal Injection–Related Endophthalmitis - COVID-19 & Physician - Patient Face Masking.

November 15, 2021

Intravitreal injections are among the most common medical procedures performed in the world, having been established as the standard of care in the treatment of many common retinal diseases including diabetic macular edema, retinal vein occlusion, and age-related macular degeneration.

The only universally accepted approach to reducing the rate of endophthalmitis is the use of povidone iodine on the ocular surface before injection with a survey demonstrating its nearly universal use for antisepsis in over 99% of retinal specialists.

The use of postinjection prophylaxis with topical antibiotics has not been found to reduce endophthalmitis rates and may increase antibiotic resistance among culture positive cases.

In addition, studies have demonstrated that surgical mask use by the physician reduces oral bacterial dispersion onto the surgical field.

This is of particular importance as a meta-analysis found about a third of culture positive postinjection endophthalmitis cases were due to Streptococcus, a normal constituent of the upper respiratory and oral cavity flora.

Streptococcus, however, is not commonly isolated from among the conjunctival flora. Given that Streptococcus-associated endophthalmitis has been found to be associated with significantly worse visual outcomes, any effort to prevent infection from this organism is paramount.

Routine use of face masks for patients and physicians during intravitreal anti-vascular endothelial growth factor (VEGF) injections has increased with the emergence of the coronavirus disease 2019 pandemic.

The risk of presumed infectious endophthalmitis does not increase following administration of anti-vascular endothelial growth factor (VEGF) injections, and universal masking (everyone, including doctor, patient, and technician) may actually decrease the risk of culture-positive endophthalmitis, according to Sunir Garg, MD, from MidAtlantic Retina, the Retina Service of Wills Eye Hospital, Philadelphia.

This is important considering the devastating consequences of endophthalmitis and the exponential increase in the administration of antiVEGF injections during the past decade.

However, because conflicting information exists about whether masking helps or hurts endophthalmitis risk, Garg conducted a study with 12 large retina practices around the country to determine whether universal masking while administering intravitreal injections during the pandemic increased the risk in the incidence of endophthalmitis.

He cited three recent studies: one indicating that thermal cameras showed face masks directed streams of air toward the eyes, another reporting that masks altered the type and amount of bacterial flora around the eye and that taping the upper portion of masks might limit bacterial dispersion, and a third showing that mask use by physicians did not alter endophthalmitis risk and, interestingly, that there were no cases of oral flora in the masked physician group.

To settle the debate, Garg conducted a retrospective comparative cohort study that included all intravitreal injections (bevacizumab [Avastin, Genentech], ranibizumab [Lucentis, Genentech], and aflibercept [Eylea,  Regeneron Pharmaceuticals]) administered between October 2019 and July 2020 in 12 US centers.

The data were divided into 2 segments: from October 2019 to March 2020, when no universal masking was in place, and from March 2020 to July 2020, when universal masking was the norm.

The primary outcome was the rate of endophthalmitis in the “universal face mask” group vs the “no face mask” group, and the secondary outcomes were visual acuity and presence of microbiologic flora.


More than 500,000 intravitreal antiVEGF injections were administered during the study period (294,514 and 211,454, respectively).

There were 85 cases of presumed endophthalmitis (0.0289%; 1 in 3,464 injections) in the no-face-mask group and 45 (0.0213%; 1 in 4,699 injections) in the face-mask group, a difference that did not reach significance (P = .097).

A closer look showed significantly (P = .041) more cases of culture-positive endophthalmitis in the no-mask group, ie, 27 (0.0092%; 1 in 10,908 injections), compared with 9 (0.0040%; 1 in 23,494 injections) in the mask group.

Garg also found 3 flora-associated cases of endophthalmitis in the nomask group and 1 in the mask group, a result that did not reach significance.


A deeper look at 18,602 of the 211,454 (9%) injections administered when taping was required to secure the top portion of the mask showed 4 cases of endophthalmitis (0.021%; 1 in 4,650 injections) and no cases of oral flora-associated endophthalmitis, a finding similar to that in the no-taping cohort.

Comparable outcomes in visual outcomes were seen between the 2 groups following endophthalmitis treatment.

“Universal masking does not seem to increase the risk of developing endophthalmitis, and it may cause a reduction in culture positive endophthalmitis,” Garg concluded. “However, even with universal masking, endophthalmitis still occurs in a small percent of cases.”

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