A comprehensive review article published in the journal Eye claims that prolonged face mask wearing due to the coronavirus disease 2019 (COVID-19) pandemic is unlikely to cause any serious complications in the eyes.
Study: Real or MADE-up: Investigating Mask-Associated Dry Eye (MADE) as an emerging syndrome. Image Credit: eldar nurkovic / Shutterstock
Background
Widespread use of face masks during the most recent COVID-19 pandemic has brought about a new eye health condition called Mask-Associated Dry Eye (MADE). This condition is characterized by many symptoms, including dryness, redness, and ocular surface irritation caused by prolonged wearing of face masks.
Pre-existing evidence suggests that Mask-Associated Dry Eye might occur due to the upward flow of air from the mask to the eyes. However, no previous evidence on such eye conditions is available for surgeons who have been using surgical masks for years.
In this review article, the authors critically analyze available evidence on mask-associated dry eye to understand the actual magnitude of its prevalence and severity.
The authors searched various scientific databases to identify full-text articles that reported Mask-Associated Dry Eye. They identified a total of 26 studies involving 14,919 participants and grouped them by study design, objective measures, subjective measures, and miscellaneous parameters.
Important observations on objective measures
Tear break-up time (TBUT) and Schirmer’s test were the most commonly used clinical examinations in the selected studies to investigate the impact of face mask use on objective measures of ocular surface irritation.
TBUT is a standard diagnostic procedure for dry eye conditions. It defines the time the first dry spot takes to appear on the cornea following a complete blink. In dry eyes, TBUT is typically less than 10 seconds. Schirmer’s test is another type of examination for dry eyes that determines whether the eyes are producing sufficient tears to maintain moisturization. A 5 mm of tear production in 5 minutes is considered to be the dry-normal cut-off value in Schirmer’s test.
Of 26 studies included in the review, 15 compared the differences in TBUT between mask-on and mask-off conditions or between shorter and longer durations of mask use. A median reduction of 1.3 seconds in TBUT due to mask use was reported by 12 studies, which appears to be clinically non-significant. As mentioned in the review, such a slight change in TBUT is not expected to cause any significant complications on the ocular surface. Thus, the findings of selected studies indicate that mask use may cause very mild changes in the tear film that covers the ocular surface for protection and lubrication.
A total of 8 studies used Schirmer’s test, of which five reported a significant reduction in tear production, and two reported a significant increase in tear production due to mask wear. An induction in tear production due to mask use is expected as the redirected exhaled air can irritate the eyes and subsequently trigger reflex tearing. In contrast, a reduction in tear production may be explained by reduced hydration, possibly as a result of behavioral changes due to mask use.
A total of 7 studies conducted corneal and conjunctival staining, of which six reported worsening due to face mask use.
Important observations on subjective measures
The Ocular Surface Disease Index (OSDI) was the most commonly used questionnaire in the selected studies. A total of 15 studies used this questionnaire to differentiate between eye conditions in mask-on and mask-off conditions. However, the majority of these studies incorrectly used the questionnaire.
Among these studies, five analyzed independent associations between mask use durations and OSDI scores. The findings revealed that heavy mask use for more than 6 hours a day is associated with significant worsening of dry eye symptoms.
Furthermore, some studies analyzed the impact of mask use on inflammatory markers, ocular surface temperature, tear soluble factors, tear osmolarity, and tear ferning tests. These studies produced mixed results. While some studies showed ocular surface pathologies due to mask use, some could not find any significant changes.
Significance
The authors have analyzed available scientific evidence on Mask-Associated Dry Eye and suggested that prolonged face mask use may cause mild ocular surface irritation; however, severe ocular surface pathology is very unlikely to occur following mask use.
An increased airflow from the mask towards the eye may trigger tear film evaporation, which in turn may cause mild ocular surface irritation or inflammation. An increased level of carbon dioxide within the face mask may also affect the ocular surface.
Considering the overall quality and certainty of selected studies, the authors mention that there is currently insufficient data to support the emergence of a new syndrome.
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