Effect of facemasks on the tear film during the COVID-19 pandemic

To evaluate the effect of wearing facemasks on dry eye symptoms and on the tear film while comparing surgical face masks to N95 particulate respirators.

A prospective observational study was conducted at Ain Shams University Hospitals in the period from September 2020 to January 2021. Two hundred volunteers were recruited, and the daily number of hours spent by each participant wearing a facemask was recorded. Recruits were divided into two groups: 100 volunteers were allocated to Group A to use the surgical mask, and 100 participants to Group B to use the N95 particulate respirator. The tear film parameters were assessed at baseline by answering the Ocular Surface Disease Index (OSDI) questionnaire and performing tear break-up time (TBUT), corneal fluorescein staining, and Schirmer-I test Subjects then wore a facemask for 60 min and then the tear film parameters were reassessed by repeating TBUT, corneal staining and Schirmer-I test.

Facemask use for 60 min significantly worsened all tear film parameters in both groups (P-value <0.0001). The deterioration was significantly larger in Group A subjects (P < 0.0001). The daily number of hours spent wearing a facemask correlated strongly with the OSDI and corneal staining. There was a strong negative correlation between the daily number of hours spent wearing a facemask and Schirmer test, and a weak negative correlation with TBUT.

Wearing facemasks during the COVID-19 pandemic is a risk factor for worsening tear film parameters. This deterioration is significantly greater with surgical masks than with N95 particulate respirators and increases with the duration of facemask use.