Effect of PPE on eye-microscope distance and target visibility
The median and range of eye-microscope measurements and target visibility calculations are shown in Table 2. The normal eye-microscope working distance, without the use of PPE (defined as level A), was between 11 and 18 mm (median 13mm). All surgeons were able to achieve a full (100%) view of the surgical field/target when not wearing any PPE (PPE level A). The use of an FFP-3 mask, with progressively bulky eye protection, increased the working distance with a resultant reduction in surgical view. The use of a full-face visor (PPE level E) reduced the area of the surgical view to a median of 4% (range 4 – 16%).