Wearing Surgical Masks, Talking During Ophthalmic Procedure May Spread Bacteria

Face masks may help limit the spread of coronavirus disease 2019 (COVID-19), but in the ophthalmologist’s office, patients may have to rethink their strategies. Researchers say that improperly sealed masks worn during certain procedures, may play a role in complications.  

Anxious patients may hyperventilate before an intravitreal injection, an American Journal of Ophthalmology publication explains. When those hyperventilating patients wear face masks, their breathing rate could further rise — theoretically increasing chances for releasing bacteria from their mouths and nose, according to the researchers. For this reason, the team behind the study propose a barrier of tape across the superior edge of masks to keep this loose bacteria from entering the injection site. Healthy subjects participated in an investigation of bacterial dispersion based on 6 face mask scenarios. The scenarios included:

• No face covering
• Loose-fitting surgical face mask
• Tight-fitting surgical mask with enclosed nose-piece contouring to the face
• Tight-fitting surgical mask including a nose-piece, secured superiorly with adhesive tape
• N95 mask
• Cloth face mask

The scenarios were tested in 2 conditions. In the first, participants were silent for 2 minutes. In the other, patients read from a 2-minute script. Although participants wearing the un-taped, tight-fitting surgical mask grew the most colony-forming units (CFUs) in both silence and speech settings, taping the entire top portion significantly reduced bacterial dispersion upward. “There was no difference between those with a tight-fitting surgical mask with tape and an N95 (fit-tested) mask under either  ‘no-talking’ (P >.99) or  ‘speech’ (P =.831) conditions,” the study demonstrates.

In the prospective cross-sectional study, simulated injection appointments were performed in standard examination lanes. The 15 participants were at least 18 years old. Investigators consistently positioned 100 mm circular blood agar plates on the subjects’ forehead, which were later submitted to the lab for analysis by microbiologists.

In the silent condition, those with un-taped tight-fitting surgical masks grew the most bacterial colonies. However, those with a taped tight-fitting surgical mask or subjects wearing an N95 grew the fewest colonies. Regarding the speech condition, subjects wearing the un-taped tight-fitting surgical mask grew the most colonies, and those wearing the N95 grew the fewest.

Previous studies have demonstrated greater bacterial dispersion when a patient speaks during an intravitreal injection appointment, but less is known about the impact for different types of face coverings now worn by patients since the pandemic began, such as cloth masks. In the current study, those wearing cloth face coverings grew a comparable amount of bacterial units in both silent and speech conditions, although the analysis did not explore taping the superior edge of cloth masks. Also in the silent condition, no significant difference in mean CFUs was found between the no face covering and cloth face mask groups (P =.831).

A limitation of the study included agar plates placed at the forehead level, which does not exactly match the intended area of the eye’s surface. Another limitation was that N95s were pre-fitted, but a number of real-world patients do not always pre-fit their N95. Thus, the benefits of taping may have been under-demonstrated.

The silent condition was also affirmed as vital regarding oral bacteria. “Indeed, in our study, there were no cases of oral flora isolated during the no talking scenarios, which further supports the efficacy of a speech reduction policy to reduce the risk of oral flora–associated endophthalmitis,” according to the investigators.

Disclosure: Several of the study’s authors declared affiliations with the biotech and pharmaceutical industries. Please see the original reference for a full list of authors’ disclosures. 

Reference

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