It’s a frightening new world optometrists are embarking on as states slowly test the waters on reopening amid COVID-19. In an effort to keep everyone as safe as possible, clinicians and staff are focusing on personal protective equipment (PPE) because social distance isn’t really an option in the office. Slit lamp breath shields, for example, have become almost indispensable. Some optometrists have designed their own breath shields, and most manufacturers now offer shields for their own equipment.¹ However, a Canadian research team took a closer look at various shields and found not all are equally protective.²

The investigators filled a spray gun filled with a colored dye and set it on the “mist” setting to simulate a sneeze. They evaluated six commercially available breath shields and one repurposed from a plastic container lid. They sprayed each breath shield in a standardized fashion three times and measured the amount of “overspray,” which they then compared with a control test without a shield.²

They found that some of the shields allowed up to 54% overspray. Breath shields that attach to the objective lens arm did a better job than those hung by the oculars of comparable size, they said. Additionally, the repurposed plastic lid breath shield had an unexpected advantage over the others. Its slight curve toward the examiner’s face allowed only 2% overspray. It was also aided by its size, at 513cm². The largest breath shield, at 1,254cm²,  performed even better, as it hung near the oculars and prevented essentially all the overspray.³

The study says that larger breath shields are preferable, but any shield should be combined with masks, gloves and handwashing to decrease the possible risk of viral transmission.²