Choroidal thickness changes in healthcare professionals wearing surgical masks or FFP2 masks: Pilot study

To evaluate the choroidal thickness (CT) with enhanced depth-imaging optical coherence tomography (EDI-OCT) in healthcare professionals using surgical masks or FFP2 (N95) masks.

We included the 120 eyes of 120 healthy volunteers who were using a surgical mask (Group 1) or FFP2 mask (Group 2) in the study. Spectral domain (SD) OCT was used to measure CT. EDI-OCT was used to measure subfoveal and perifoveal CT. Points 1500 μm nasal (C_N1500) and temporal (C_T1500) to the foveal center were used to measure perifoveal CT. Oxygen saturation and heart rate were measured with a pulse oximeter. All measurements were performed at 8:30, before wearing the mask, and at 12:30, when the mask was removed for the lunch break.

Of a total of 120 subjects, Group 1 consisted of 60 subjects (mean age 38.50±8.60 (range 24-44) years) and Group 2 also consisted of 60 subjects (mean age 36.60±6.53 (range 26-45) years). Although not statistically significant, CT was seen to have increased at 3 measurement points in Group 1 after using the mask for 4 h: subfoveal CT (C_SF) (p = 0.545), C_T1500 (p = 0.080), and C_N1500 (p = 0.251)). In Group 2, the increase in C_SF (p = 0.001) was statistically significant while the increases in C_N1500 and C_T1500 were not (p = 0.162 and p = 0.058, respectively) after using the mask for 4 h.

We found CT to increase after 4 h of mask use, and this increase was more marked in Group 2. The increase in subfoveal CT in particular was statistically significant in Group 2.