Amid growing evidence of the novel coronavirus being able to spread through aerosols in closed spaces, medical health professionals and scientists are putting their heads together to study risks associated with aerosols generated during surgeries and out-patient procedures.
Doctors at Narayana Nethralaya, Bengaluru, have collaborated with researchers at the Indian Institute of Science (IISc.) to investigate how aerosols — tiny droplets that can remain suspended in air for hours in closed spaces — are generated during routine eye procedures.
High-speed imaging and aerodynamic models were used to visualise the generation of droplets during procedures such as cataract and LASIK surgeries. The size of the droplets were identified and the researchers calculated the speed and distance to which they travel. The studies showed that during most procedures, aerosols are not generated, Saptarshi Basu, professor, Department of Mechanical Engineering, IISc., and co-author of two papers published in the Journal of Cataract and Refractive Surgery, was quoted as saying in an IISc. press release.
The first study focused on phacoemulsification, a type of cataract surgery where an ultrasonic needle is used to break up the cataract. The fluids are then suctioned out and the eye is rehydrated with a balanced salt solution. The researchers employed a technique called shadowgraphy, which uses a light source such as pulsed laser or LED to cast shadows of fast-moving droplets onto the sensor of a high-speed camera, the release stated. It added that no aerosols were generated when the probe was restricted to the inner layer of the eye called anterior chamber, but when the probe was exposed to the salt solution on the eye’s outer surface called cornea, aerosols were formed. The researchers have suggested replacing the salt solution with more gelatinous or viscous materials to prevent fluid spurting and aerosol generation.
Droplets travel
In the second study during LASIK surgery performed to correct near or far-sightedness, researchers found that the oscillating blade cut through the stroma (the inner layer of the cornea), some droplets were generated, likely owing to the balanced salt solution used as a lubricant prior to the procedure. However, most of the droplets were found to be large in size and therefore likely to settle down fast, reducing the risk that they will become aerosolised. “Because the droplets were found to travel up to 1.8 m in a simulated surgery setting, adequate precautions and protective equipment should be adopted by doctors,” the researchers have suggested.
The release added that based on these findings, the hospital has identified and implemented specific safety protocols. Similar studies have been planned for orthopaedic and heart surgeries.
