A viral video with real world impact

​This mannequin’s oral cavity was fitted with a latex balloon filled with compressed oxygen and dye to simulate a patient’s cough during an eye examination

In the early days of the COVID-19 pandemic, the ophthalmology community had one pressing question: How can we keep everyone safe, when our practice involves such close contact?

"In ophthalmology, we can't really maintain any distance from patients because our exams are right in front of their faces," explains Dr. Efrem Mandelcorn, a retinal surgeon and clinician investigator at the Donald K. Johnson Eye Institute's Retina Clinic and Sprott Department of Surgery at UHN.

To determine how to lessen viral exposure, Dr. Mandelcorn and a team of his colleagues created a series of experiments that quickly had significant, real-world impact.

The team placed a small latex balloon filled with compressed oxygen and fluorescent dye inside a mannequin's oral cavity. The unmasked mannequin was placed in the patient's position in front of a slit-lamp, the instrument routinely used during eye examinations. A live examiner donned personal protective equipment and took their place opposite the mannequin. When the balloon burst, it simulated a cough from a patient by ejecting dye droplets. The spray, picked up under ultraviolet light, covered the examiner's upper body and equipment.

However, when the mannequin wore various types of masks, including cloth, surgical and N95 varieties, the spread either decreased or disappeared entirely. Findings suggested that wearing a well-fitting cloth mask properly is more effective than wearing a surgical mask incorrectly. And N95 masks are the most effective of all.

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