BLOG: MADE: A new coronavirus-associated eye disease
It’s been strange these last 6 weeks or so. All of these new dry eye disease patients. Even for a high-volume dry eye center, there sure were a ton of new cases coming in.
What was especially weird was the fact that so many of them were long-term patients at SkyVision and had previously been free of any signs or symptoms of DED whatsoever. You know that feeling when something is sorta wrong, you know it’s sorta wrong, but what’s wrong stays just barely beyond conscious thought? That’s what it was like.
Then it hit me. One of my long-tenured patients was in, his first foray outside of his assisted living home, complaining about decreased vision in an eye that was already 20/100 due to anterior ischemic optic neuropathy. He was flustered and flummoxed with his mask and his glasses. They would cartoonishly fog with each exhalation, clear as he inhaled, only to fog up all over again. “They make us wear these damn things whenever we are out of our own apartment.” Sure enough, his vision was now 20/200 in that “bad eye,” and it was down two lines in the good one. Nothing was different on his exam except 2+ confluent superficial punctate keratitis on the lower third of each cornea.
All this time, it was right there in front of me. That airflow fogging up my patient’s glasses doesn’t miraculously disappear if you take the glasses off, right? Of course not. Exhaled air is funneled upward and across the surface of the eyes by any mask that is not tightly fitted to the face. It’s no different from the flow of air that messes with your DED patient’s vision and comfort when they drive for long periods with the defroster or heat/air vents on. Moving air across a moist surface encourages evaporation leading to — wait for it — a dryer surface.
Let’s call this mask-associated dry eye, or MADE. In my early experience, it does not seem to be more or less prevalent in any particular population. Patients with preexisting DED tend to have more discomfort while “new onset” DED tends to bring more visual symptoms. For you DED geeks out there, I’d like to pose a hypothesis on the pain thing. Air flow leads to evaporation, which in turn leads to a cooling of the cornea. We know that aberrant firing of cold-sensing sensory nerves in the cornea is felt to be one underlying cause of neurogenic pain. It makes sense that flow-driven cooling would lead to more discomfort in eyes that may be sensitized by existing DED.
I think this is a real thing. To prevent fogging of slit lamp or OR microscope oculars, I typically use an adhesive mask. While out grocery shopping, I noticed that my eyes were super sore as I was leaving the store. Sure enough, I was wearing a fabric mask that contained a HEPA filter (reducing horizontal flow) and did not have adhesive securing it to my nose and cheek (allowing vertical flow). Count me among the sufferers of MADE, the newest malady associated with COVID-19.
Editor’s note: This article’s headline was updated on Aug. 26, 2020.