RESUMEN
OBJECTIVE: To compare tear fluid levels of matrix metalloproteinase 9 (MMP-9) and IL-1ß cytokines between healthcare workers wearing facial masks and controls with correlations in clinical findings. METHODS: In a prospective, controlled clinical trial tear fluid was analyzed for MMP-9 and IL-1ß levels using a commercially available test (Invitrogen; Thermo Fisher Scientific Inc. Waltham, Massachusetts, USA). Symptoms and signs of dry eye disease (DED) were evaluated using the ocular surface disease index (OSDI), noninvasive tear break-up time (NIBUT), tear meniscus height (TMH), Oxford corneal staining, meibomiography, and clinical findings of meibomian gland dysfunction (MGD). RESULTS: In the 38 eyes of healthcare workers and 30 eyes of controls, there was no statistically significant difference between the groups in terms of age and sex (p > 0.05). The mean OSDI score, daily mask wear time, meibomiography degree, and rate of positive clinical findings of MGD were higher in group 1 than in group 2, and the mean NIBUT was higher in group 2. (p > 0.05). The mean values of IL-1ß and MMP-9 were higher in group 1 (p = 0.036 and p = 0.001, respectively). The TMH and Oxford score percentages were similar between the two groups (p > 0.05). CONCLUSIONS: Elevated levels of IL-1ß and MMP-9 in the basal tear fluid reveal increased ocular inflammation in healthcare professionals. Lower NIBUT values with higher OSDI and meibomian gland loss scores support ocular surface disturbance depending on regular mask use.