Influence of short-term face mask wear on semiautomatically measured tear film parameters in dry eye patients and healthy volunteers

Abstract

Purpose: The use of face masks has been proposed to cause or exacerbate the symptoms of dry eye disease (DED), which has been widely discussed under the term mask-associated dry eye (MADE). However, no studies have systematically investigated tear film parameters during the use of different face masks. Therefore, the objective of the present study was to investigate clinically relevant parameters of the tear film before and during the short-time use of face masks in dry and normal eyes.

Methods: In a prospective study, the tear film parameters of 42 DED patients and 42 healthy volunteers were examined while wearing different types of face masks in a randomized order. This included measurements of non-invasive tear break-up time (NIBUT), lipid layer thickness, tear meniscus height, and bulbar redness after 30 min of wearing no mask, a surgical face mask or an FFP2/K95 mask. The equivalence of the means was assessed using the two one-sided t-test (TOST) method.

Results: In healthy volunteers' lipid layer thickness, NIBUT and tear meniscus height were not significantly altered by 30 min of surgical or FFP2 mask wear (p > 0.016). The use of either type of mask was significantly associated with decreased bulbar redness (p < 0.001) in healthy eyes. In patients with DED, none of the tear film parameters or bulbar redness were significantly altered by 30 min of mask wear (p > 0.016).

Conclusions: Based on these results, the short-term wearing of face masks, regardless of type, did not produce a significant difference in tear film parameters of lipid layer thickness, NIBUT, and tear meniscus in healthy or dry eyes, while bulbar redness was reduced after mask wear only in healthy volunteers.

Keywords: Dry eye; Face masks; Lipid layer thickness; NIBUT.

Fig. 1

Bland–Altman diagrams of lipid layer thickness (LLT) measurements. Each dot represents the average of two LLT measurements (in nm, x-axis) of the same eye and the difference between them (y-axis). The horizontal blue line shows the mean difference of both measurement results, and the red lines show the limits of agreement. Panels A–C show measurements in healthy subjects, panels D–F show measurements of dry eye patients (DED). A, D: FFP2 mask vs. no mask; B, E: surgical mask vs. no mask; C, F: FFP2 mask vs. surgical mask

Fig. 2

TOST of lipid layer thickness (LLT) measurements. The black square shows the mean difference of the two compared LLT measurements. The horizontal line shows the 96.8% confidence interval. The dashed vertical lines show the equivalence limits. Panels A–C show measurements in healthy subjects, panels D–F shows measurements of dry eye patients (DED). A, D: FFP2 mask vs. no mask; B, E: surgical mask vs. no mask; C, F: FFP2 mask vs. surgical mask

Fig. 3

Bland–Altman diagrams of non-invasive tear break-up time measurements. Each dot represents an average of two NIBUT first break measurements (in seconds, x-axis) of the same eye and the difference between them (y-axis). The horizontal blue line shows the mean difference of both measurement results, and the red lines show the limits of agreement. Panels A–C show measurements in healthy subjects, panels D–F show measurements of dry eye patients (DED). A, D: FFP2 mask vs. no mask; B, E: surgical mask vs. no mask; C, F: FFP2 mask vs. surgical mask

Fig. 4

TOST of non-invasive tear break-up time measurements. The black square shows the mean difference of the two compared NIBUT measurements. The horizontal line shows the 96.8% confidence interval of the mean difference. The dashed vertical lines show the equivalence limits. Panels A–C show measurements in healthy subjects, panels D-F show measurements of dry eye patients (DED). A, D: FFP2 mask vs. no mask; B, E: surgical mask vs. no mask; C, F: FFP2 mask vs. surgical mask