Altered Ocular Surface Health Status and Tear Film Immune Profile Due to Prolonged Daily Mask Wear in Health Care Workers

Abstract

Prolonged daily face mask wearing over several months might affect health of the ocular surface and is reported to be associated with complaints of discomfort and dry-eye-like symptoms. We studied the ocular surface clinical parameters, tear soluble factors and immune cell proportions in ophthalmologists practicing within similar environmental conditions (n = 17) at two time points: pre-face-mask period (Pre-FM; end of 2019) and post-face-mask-wearing period (Post-FM; during 2020 COVID-19 pandemic), with continuous (~8 h/day) mask wear. A significant increase in ocular surface disease index (OSDI) scores without changes in tear breakup time (TBUT), Schirmer’s test 1 (ST1) and objective scatter index (OSI) was observed Post-FM. Tear soluble factors (increased—IL-1β, IL-33, IFNβ, NGF, BDNF, LIF and TSLP; decreased—IL-12, IL-13, HGF and VEGF-A) and mucins (MUC5AC) were significantly altered Post-FM. Ex vivo, human donor and corneoscleral explant cultures under elevated CO2 stress revealed that the molecular profile, particularly mucin expression, was similar to the Post-FM tear molecular profile, suggesting hypercapnia is a potential contributor to ocular surface discomfort. Among the immune cell subsets determined from ocular surface wash samples, significantly higher proportions of leukocytes and natural killer T cells were observed in Post-FM compared to Pre-FM. Therefore, it is important to note that the clinical parameters, tear film quality, tear molecular factors and immune cells profile observed in prolonged mask-wear-associated ocular surface discomfort were distinct from dry eye disease or other common ocular surface conditions. These observations are important for differential diagnosis as well as selection of appropriate ocular surface treatment in such subjects.

Face mask use and effects on the ocular surface health: A comprehensive review

“…Hypercapnia also is known to induce inflammation, although the effects on the ocular surface have not been thoroughly investigated [ 17 ]. Nevertheless, D'Souza et al hypothesized that the increased carbon dioxide in the exhaled air flowing over the ocular surface may induce hypercapnia-related changes and alter the molecular profile [ 18 ]. The exhaled air is usually warmer than the environment and these changes in temperature might also promote tear evaporation [ 19 ].…”

“…Large surveys have used non-standardized questionnaires, although other authors have observed an increase in Ocular Surface Disease Index (OSDI) scores with the use of face masks [ 18 , [43] , [44] , [45] , [46] , [47] ]. This increase was mainly due to an increase in the discomfort and the vision scales [ 18 ].…”

“…However, other groups have obtained different results. For example, D'Souza et al [ 18 ] observed an increase in Schirmer's test 1 and TBUT scores in healthy patients. This increase in tear quality parameters, did not seem to match the high OSDI scores obtained in that study.…”

“…Studies on this topic are scarce, the main work being D'Souza et al‘s, which investigated the levels of different cytokines before and after face mask use [ 18 ]. A number of proinflammatory factors were significantly increased in the post face mask samples.…”

“…In addition, D'Souza et al analyzed the ocular surface immune cell profile, obtaining significantly higher proportions of leukocytes and natural killer T cells in post face mask use samples, along with a significant reduction in the proportions of eosinophils, B cells and plasma cells [ 18 ]. This differs from the immune cell profile seen in dry eye disease patients, suggesting a different inflammatory mechanism [ 61 ].…”