Effect of Taping Face Masks on Quantitative Particle Counts Near the Eye: Implications for Intravitreal Injections in the COVID-19 Era

Abstract

Purpose : While one might expect that universal masking would decrease the risk of oral flora contamination during the injection procedure, anecdotal reports of oral flora-related endophthalmitis during COVID-19 have emerged. We performed a prospective observational cohort study to determine the effect of taping the top of face masks on air particle counts directed toward the eye during simulated intravitreal injections.

Methods : Thirteen healthy N95 qualitative fit tested human subjects were recruited, three women and ten men, with an age range of [24, 35]. Each wore a cloth, surgical, or N95 mask in randomized order. The number of air particles were quantified using a particle counter suspended over the right eye while each subject breathed normally, deeply, or spoke using a standardized script. Particle counts were obtained with the top of each mask taped and untaped. The main outcome measurements were particle counts in the size classes of 0.3 mm, 0.5 mm, 1 mm, 3 mm, 5 mm, 10 mm, and total particle count. The Wilcoxon signed rank test was used to test for paired differences between taped and untaped particle counts for each combination of mask type and respiratory mode, at each particle size.

Results : Taping cloth masks while subjects were speaking significantly reduced particle counts for the size classes of 0.3 mm (p=0.03), 0.5 mm (p=0.01), 1 mm (p=0.03), and total particle counts (p=0.008) compared to no taping. Taping the top of cloth masks during normal or deep breathing did not significantly affect particle counts compared to no taping. Taping the top of surgical or N95 masks did not significantly alter particle counts for any breathing condition tested.

Conclusions : Taping the top of cloth masks prior to simulated intravitreal injections significantly reduced air particle counts directed toward the eye when subjects were speaking compared to no taping. This may have implications for decreasing air particles reaching the eye during intravitreal injections, including aerosolized droplets from a patient’s mouth that may carry oral pathogens.

This is a 2021 ARVO Annual Meeting abstract.