Droplet Spread Reduced With Breath Guards, Masking

Larger breath guards and face masks may significantly limit droplet spread in eye care clinics.

A larger breath guard may significantly reduce the spread of droplets within an eye clinic, according to research published in Eye. Combined with masking, the spread of droplets may be reduced by over 99.98%, the report shows.  

Researchers conducted a randomized trial to measure droplet spread using a fluorescein-based cough model. The method involved collecting simulated cough spray on calibrated paper targets and photographing the sheets in blue light conditions with an orange filter. 

A total of 44 randomized coughs were performed which included 22 with no breath guard or face-mask used (controls), 11 with a breath guard only, and 11 with both a breath guard and face mask. Once the simulated coughs were completed, the research team compared the number of droplets for all 3 conditions and measured the area of the drops left on the paper targets. 

Overall, there were 19,430 droplets following the control cough compared with 80 drops after installing the breath-guard (P <.001), and 5 drops after both a breath guard and face mask were used (P =.008). There was a 99.93% decrease in droplet spread with the use of a breath guard and a 99.98% decrease with the use of both a breath guard and face mask, according to the report.   

Larger breath guards significantly reduced the droplets spread, with the addition of face-masks very few droplets spread from the patient.

“Larger breath-guards significantly reduced the droplets spread, with the addition of face-masks very few droplets spread from the patient,” according to the researchers. “However, the breath-guards are not protective against the smallest droplets such as aerosols, these will remain airborne for many minutes, and may affect the physician as well as the patient and subsequent patients. Good ventilation is important as well and the air turnover is recommended at 10 cycles per minute.”

This study was limited by the inability to accurately measure the aerosol release.


Newsom R, Pattison C, Lundgren A, Robison P, Quint M, Amara A. Comparison of breath-guards and face-masks on droplet spread in eye clinics. Eye. Published online December 3, 2022. doi:10.1038/s41433-022-02308-8