Tag: Face Masks

Advice directly from the Annals of The Royal College of Surgeons of England,

TECHNIQUE

Immediately before wearing a face mask, wash the spectacles with soapy water and shake off the excess. Then, let the spectacles air dry or gently dry off the lenses with a soft tissue before putting them back on. Now the spectacle lenses should not mist up when the face mask is worn.

DISCUSSION

The face mask directs much of the exhaled air upwards where it gets into contact with the spectacle lenses. The misting occurs from the warm water vapour content condensing on the cooler surface of the lens, and forming tiny droplets that scatter the light and reduce the ability of the lens to transmit contrast.1 The droplets form because of the inherent surface tension between the water molecules. Washing the spectacles with soapy water leaves behind a thin surfactant film that reduces this surface tension and causes the water molecules to spread out evenly into a transparent layer. This ‘surfactant effect’ is widely utilised to prevent misting of surfaces in many everyday situations.

We are definitely Team Mask around my house. Ordered a bunch of cloth masks from Etsy last week. Here’s my daughter modeling her minion facemask.

I think the masks have a side benefit beyond whatever protection they might offer from spreading or contracting COVID-19. They also signal to people around us that we are taking preventing the spread of the virus seriously (well, as seriously as one can with a minion mask).

Too often I have been out for a walk in my neighborhood or at the grocery store, and people are completely oblivious to social distancing recommendations. Wearing the masks seems to have some effect on other people’s behavior in improving that distancing so far.