Cough simulation highlights infection spread

International ophthalmologists have developed a video simulation demonstrating that slit lamp breath shields do not provide full protection from respiratory droplets, however droplet spread is minimised significantly when patients wear a mask.

In a demonstration posted by the American Academy of Ophthalmology this month, Dr Tina Felfeli, Dr Efrem Mandelcorn and colleagues used ultraviolet conditions to assess the spread of respiratory droplets when a patient coughed during a slit lamp examination.

The findings highlight the need for patients to wear a mask during close clinical encounters, including a well-fitted cloth mask if it is the only available option, reported Insight News.

The simulation involved a mannequin placed at the chin rest of the slit lamp fitted with a common commercially available breath shield measuring 9.75 inches by 10.5 inches (24.75cm by 26.67cm).

The patient cough was reproduced using a latex balloon filled with fluorescent dye, which was inflated with compressed air to burst at 5psi – previously reported as the psi level for a voluntary cough.

Following the simulation, droplets were located on the upper body of the examiner and the slit lamp. Overall it demonstrated that slit lamp breath shields minimise but do not eliminate the spread of respiratory droplets on the examiner.