Quantitative High-speed Assessment of Droplet and Aerosol from an Eye after Impact with an Air-puff Amid COVID-19 Scenario.

Purpose To quantify aerosol and droplets generated during non-contact tonometry (NCT) and assess the spread distance of the same. Methods This was an experimental study on healthy human volunteers (n=8 eyes). In an experimental set up, NCT was performed on eyes (n=8) of human volunteers under normal setting, with a single and 2 drops of lubricant. High speed shadowgraphy, frontal lighting technique and fluorescein analysis were used to detect the possible generation of any droplets and aerosols. Mathematical computation of the spread of the droplets was then performed. Results In natural setting, there was no droplet or aerosol production. Minimal splatter along with droplet ejection was observed when 1 drop of lubricant was used prior to NCT. When 2 drops of lubricant were instilled, we noted significant amount of fluid ejection in the form a sheet which broke up into multiple droplets. Some these droplets traversed back to the tonometer. Droplets ranging from 100 to 500▒µm in diameter were measured. Conclusions There was no droplet generation during NCT performed in natural setting. However, NCT should be avoided in conditions with high tear volume (natural or artificial) as it would lead to droplet spread and tactile contamination.