Objective: As an aerosol generating procedure (AGP), mastoidectomy in the COVID-19 era requires healthcare workers to wear personal protective equipment (PPE); UK guidelines recommend an FFP-3 mask and full-face visor. The aim of this study was to examine the effect of wearing PPE on the view achieved using the operating microscope. Methods: Using the operating microscope, ENT surgeons were asked to view a target so that it filled the entire operating field. The distance between the surgeon’s eye and the microscope was recorded and subsequently measured with the surgeon wearing a range of PPE. In each PPE condition, surgeons scored the visibility of the target; scores were used to calculate the visible area of the surgical field. Results: Eleven surgeons took part, generating 51 eye-microscope and target-view scores. Distance from the eye to the microscope inversely correlated with diameter and area visible (Pearson correlation coefficient -0.983 and -0.894 respectively; p<0.001). Use of PPE increased the eye-microscope distance and reduced the surgical view. The median area visible wearing the FFP-3 mask and full-face visor was 4% (range 4 – 16%). Conclusion: PPE consisting of an FFP-3 mask and full-face visor is incompatible with use of the operating microscope, with less than 10% of the surgical field visible in most cases. Solutions that allow for concurrent use of the operating microscope and drill during mastoid surgery are urgently required so that surgeons are adequately protected from COVID-19 transmission.