Slit-lamp breath shields: Larger is better for protection from coronavirus during exams

November 16, 2020
Lynda Charters

When it comes to using a breath shield as protection against the spread of the coronavirus, bigger may be better, according to investigators.


Breath shields were initially thought to improve the safety of eye examinations during the COVID-19 pandemic, and recent evidence now positively supports that position, and larger shields are more effective than the standard small shields or no shields at all.

Because spread of pathogens can occur readily during the close confines of an ophthalmic examination, Mong-Loon Kuet, MBBChir, FRCOphth, from the Department of Ophthalmology, Royal Derby Hospital, University Hospitals of Derby and Burton National Health Service Foundation Trust, Derby, UK, and colleagues saw the need to assess how well different size shields work in response to the pandemic.

To do so, they used spray dye to see any droplets that were dispersed into the air as the result of a person coughing or simply exhaling with and without use of a shield. In addition, they tested two different sized shields to see if the size of the shield really does matter.

The large shield was 45 by 44 centimeters and the results were compared with those obtained using the small standard shield that is 11 by 11 centimeters.

Finally, these results were compared with no breath shield.

The investigators reported that the large breath shield provided the best protection by stopping the spread of droplets when patients were coughing or breathing.

However, the standard shield was not adequate for preventing spread of droplet that dispersed from coughing.

“We hope that the findings will further encourage the universal use of larger breath shields as an important part of a health care provider’s infection control measures,” Dr. Kuet said.

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