Ocular Protection Not Used During Elective Cochlear Implant and Mastoid Surgery During Covid‐19 Era

Dear Editor,

We read the recently published paper by Lawrence et al ¹ with great interest and congratulate the authors for adding to our knowledge of safe otology practice in these difficult times. What was most striking to us is that none of the fluorescent fluid was seen in the eye area when the surgeon drilled both with or without the microscope tent cover. This suggests that the eye remains a body part at low risk of ingress during mastoid surgery.

In May 2020, we restarted elective surgery at the Scottish Cochlear Implant Centre. Patients and their families were strictly shielded for 2 weeks preoperatively, and all adults were required to undergo negative Covid swab testing the day before surgery. We decided not to use the eye protection available in Scotland (which must be single use) as it significantly interfered with the surgical field and the fitting of the filtering facepiece code P3 (FFP3) masks. To date, we have done 24 cochlear implants without any patient or surgeon infections. These data continue to be entered into a UK‐wide audit of otological procedures and protective personal equipment (PPE) used in the Covid‐19 era, coordinated by the British Society of Otology.

We bring in the microscope to assist at all drilling stages as we feel that it confers protection from bone dust/droplets to the surgeon and team. We have tried the well‐described microscope “tent” technique but found it unreliable and difficult to adopt.

Our stance is supported by a recent review ² of the molecular basis for hypothesized ocular transmission of Sars‐Cov‐2, which concluded that “coronaviruses are unlikely to bind to ocular surface cells to initiate infection” for the following reasons:

Although ACE‐2 receptor mRNA is found in corneal tissue, it is at between 10% and 50% of the level found in other tissues; Cofactors (TMPRSS2 or Furin proteins) that allow binding of the spike protein of Sars‐Cov‐2 to the ACE‐2 receptor are absent or reduced.

One of the drawbacks of the study was the lack of qualitative fit testing for the FFP3 mask when used alongside reusable eye protection. Through personal correspondence with the lead author, the team acknowledge that this would have been desirable but was understandably limited due to the concern about dwindling PPE availability at that time.

We would make the case that the microscope should provide sufficient protection in this particular cohort, particularly when the patients are shielded and tested for Covid‐19 preoperatively.