Respiratory Droplets Transmitted During Slit-Lamp Exams
By Lynda Seminara
Selected By: Richard K. Parrish II, MD
Journal Highlights
American Journal of Ophthalmology, February 2021
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Shah et al. constructed a simulated slit-lamp examination to evaluate the effectiveness of personal protective equipment worn during the exam. They found that wearing a mask reduced the spread of simulated respiratory droplets—and that adding a slit-lamp shield provided extra protection.
For this study, the researchers used a pressurized spray canister to simulate both patient breathing and coughing. The canister contained fluorescent material, which was sprayed and then viewed using a handheld ultraviolet flashlight. The researchers measured the velocity and distance of particle emissions for “breathing” and “coughing”—and then assessed the ability of surgical masks and slit-lamp shields to block the droplets. (Model 3D printed heads served as stand-ins for human patients and clinicians.)
Without a slit-lamp shield or masks in place, the fluorescent droplets were widely dispersed. With both the coughing and breathing simulations, droplet dispersion was lowest when both patients and clinicians wore masks; however, particles still escaped from the top of the patient’s mask, lateral to the nose. Although the slit-lamp shield blocked most of the dispersed particles, a substantial amount reached the slit-lamp joystick and table.
The original article can be found here.