Visual Field Artifacts From Face Mask Use

Abstract

Purpose: The coronavirus (COVID-19) pandemic has had a profound impact on how glaucoma care is delivered, necessitating reduced clinic flow, social distancing, and use of face coverings by patients and staff. This case highlights the need to be aware of improperly fitted face masks as a cause of artifact on standard automated perimetry (SAP). Clinical Presentation: A 32-year-old female underwent SAP with the 24-2 SITA Fast test of the Humphrey Field Analyzer wearing an ear-loop surgical face mask. At the end of testing, it was noted that the mask had ridden up the patient’s face. Small amounts of condensate were noted on the perimeter lens. Clinical Findings: SAP demonstrated good reliability indices but in both eyes, there was a marked reduction in sensitivity inferiorly. The glaucoma hemifield test was outside normal limits. It was ensured the upper border of the mask was well sealed with the loops secured around the ears and nasal strip of the mask pinched down. Visual fields were repeated and were found to be normal. Conclusions: Poorly fitting face masks represent a new cause of visual field artifact which may mimic pathologic field defects. Without careful attention during testing, the cause of such artifacts may not be apparent, especially as reliability indices may be normal. Adjustments to the fit of face masks may help prevent fogging or mask slippage and increase test reliability.

Mouth-nose masks impair the visual field of healthy eyes

“…To the best of our knowledge, the data of the present study are the first ones investigating an impairment of visual field due to mouth-nose-masks in healthy eyes. Only two recent case reports had previously shown visual field artefacts from using a mouth-nose-mask in clinical visual field testing due to fogging of the trial lens [ 16 , 17 ]. The mask can be taped to the nose [ 16 ] or can be tied around the head with a special technique, in which the superior and inferior ties cross before the ear in order to reduce fogging [ 18 ].…”

“…Therefore, people have been wearing many different kinds of masks, sometimes home-made or ill-fitting. Two case reports have already reported about visual field artefacts from using a mouth-nose-mask in clinical visual field testing by fogging of the trial lens or incorrect wearing of the mask [ 16 , 17 ]. Considering different sizes and shapes of the mouth-nose-masks, there might be different effects of visual field restriction.…”

Avoiding mask-related artefacts in visual field tests during the COVID-19 pandemic

“…In pattern A, the median number of new locations with a sensitivity lower than 95% considered normal was 14 (6-26), with a median sensitivity of −4.94 dB (−12.86 to −2.33). In pattern B, the median number was 6.5 (3)(4)(5)(6)(7)(8)(9)(10)(11), with a median sensitivity of −5.38 (−9.14 to −3.83). The median number of locations already affected in the pre-COVID test whose sensibility impaired in VF test 1 was 4 (0-17) in pattern A and 9 (2-20 in pattern B).…”

“…A recent report has shown that wearing a face mask while performing a VF test may cause inferior artefacts due to the fog on the trial lens. 4 Furthermore, face masks seem to be a distracting factor to make a reliable test, as patients refer to feeling uncomfortable and short of breath.…”

Side-Effects of Public Health Policies Against COVID-19: The Story of an Over-Reaction

“…Face masks represent a new cause of visual field artifacts that may mimic pathologic field defects: indeed, they block the vision of one's lower far peripheral visual field, which is crucial for visuomotor feedback when engaged in walking. And the fact that one is visually handicapped when wearing a face mask is almost never consciously realized [46], when it is a major public health problem [47] because: 1. Falls are the second leading cause of accidental or unintentional injury deaths worldwide, 2.…”