Since the pandemic, face mask wear has become a way of life for many across the globe to reduce COVID-19 transmission, but new research corroborates anecdotal findings that this practice can cause dry eye disease (DED)-related issues for individuals with moderate-to-severe dry eye; namely, a decrease in their tear film stability.

Investigators from Spain enrolled 31 patients who were roughly 58 years old and mostly female (97%). Researchers recorded the participants’ first and average noninvasive tear film break-up time (TBUT) with the Oculus Keratograph 5M and took measurements with the patient wearing a mask and without one 10 minutes later.

The first noninvasive TBUT reading with a face mask was 6.2 seconds, which increased to 7.8 seconds without one—a difference of 1.6 seconds. The average noninvasive TBUT measurement with a face mask was 12.3 seconds and increased to 13.8 seconds without the use of mask—a difference of 1.5 seconds.

The authors attributed the tear film instability to several possibilities. First, if the mask was displaced or incorrectly fit, the air that is exhaled rises and may leave the upper part of the mask, which could reach the eye and cause the tear film to evaporate, resulting in a poor lubricated ocular surface, they suggested in their report in the Cornea journal.

The use of powered air-purifying respirators and protective integrated hood/masks may also increase the perception of eye dryness and epithelial, punctate keratopathy due to how the full facepiece directs air upward toward the eyes, the researchers added.

Another potential reason: The use of taped masks to prevent air convection toward the eyes may interfere with the normal lower eyelid position, which could induce mechanical ectropion and tear evaporation, they said.

“The key role of the tear film and its stability as a barrier against pathogens should also be considered,” the team wrote in their paper. “Increased tear evaporation because of mask use, along with increased eye rubbing and face touching behaviors because of discomfort

symptoms, may alter the ocular surface and worsen tear film breakdown.”

In light of the findings, eye care practitioners should increase their awareness of worsening DED symptoms during COVID-19, the authors suggested. 

“Emphasis should be made to avoid mask displacement or incorrect fitting that contributes to air leaking among patients with DED and consider increasing treatment for long-term mask users if there is previous history of DED, recent ophthalmic surgery or other surface inflammatory diseases,” they wrote. 

Still, the use of face masks remains crucial during the pandemic, and patients with moderate-to-severe dry eye shouldn’t be dissuaded from wearing one, the authors concluded.