For sure, COVID-19 is primarily a respiratory disease. And for people with asthma and a history of lung disease, this virus, which has killed more than 5 million people in this country alone, is a horror. But like any true horror with destructive intent, COVID-19 doesn't just enter a person's body through one or two points of entry, in this case the nose or the mouth. COVID-19 has a special affiinity for cells of the central nervous system; in medical-speak, it is considered neurotropic. And, just to be thorough here, COVID-19 is also considered neurovirulent: It can cause disease.

The senses are part of the central nervous system.

Studies have shown for months that the eyes could act as a entry point for the virus. Here is why: When your eyes tear, they don't just run down your face; they can drain down your throat. This is how the virus can enter your body through your eyes. A study involving 535 COVID patients in Wuhan, China, found that while a few, 27, had pink eye, 343, or 64%, had the virus in the mucus in the back of their nose.

The eyes are taking a beating from another angle due to the pandemic: from the face masks. Now no one is suggesting, even flat-out saying, don't wear a mask. What they are saying is, wear the mask properly. (And keep your hands away from your face.)

Medical Daily called a few ophthalmologists around the country to see what they are seeing in their practices. The interviews have been edited.

Medical Daily: What issues can wearing a mask cause? What are you seeing in your practice in Seattle, Dr. Periman?

Laura Periman, MD: When masks don’t fit the upper face properly, the eyes are exposed to turbulent air from exhalation of the breath. The tear film [the liquid layer that bathes the visible part of the eye] can dry out from this exhalation.

MD: And in your practices in New Jersey and Pennsylvania, Dr. Matossian?

Cynthia Matossian, MD: Mask-wearing can hasten contact lenses to dry out faster.

MD: What other problems are you seeing in your clinics?

CM: We are seeing an increased number of patients with [a worsening] of their [existing] dry eye due to increased screen time. This is not only from work, but also from streaming movies, binge watching TV shows and so on, and possibly a higher number of chalazi, although we did not do a study, this is just a perception. Chalazia are clogged meibomian glands that have become infected, tender and swollen. (Meibomian glands line the inside of the eyelid. They are filled with an oily substance that is excreted on to the eye to keep it moist.)

LP: We are seeing a significant increase in dry eye symptoms in our ophthalmology patients. We are also seeing a significant increase in styes and chalazia. All of this is on top of the ocular complications we are seeing, such as pink eye, or conjunctivitis and uveitis. (The uvea is the middle portion of the eye between the retina and the white part of the eye called the sclera.)

MD: Are you seeing similar issues in your practice in Virginia, John Sheppard?

JS: Yes to all of the above, and more!

MD: What is the source of these increased conditions?

LP: We don't know exactly ... Doctor chat groups and [peer-reviewed] publications are discussing increases in the other inflammatory, neurotropic ... complications of COVID-19.

MD: How should the mask be secured?

LP: . [You can] take 1-inch medical tape and secure it half and half across nose and cheeks, and when you take it off, do it gently.

Medical Daily is aware of your work with natural cosmetics, Dr. Periman; any advice in application?

LP: If you use eyeliner, don’t tight-line the eyelids. It blocks the oil glands from delivering protective oils to the tear film and cornea. Also don’t use glued-on eyelashes...COVID is airborne and [the virus] won’t be deflected by long lashes.

MD : Anything else?

LP: Lots of eye cosmetics are full of ingredients that contribute to inflammation, increasing the source of irritation to the eyes.. You should replace any makeup that is wet, including creams and mascaras, with pumps, so there is no contamination. Products should be paraben free.

Cynthia Matossian, MD, is the founder, CM Associates, LLC, with offices in Penna. and N.J. and a VP of the American College of Eye Surgeons

Laura Periman, MD, founder and director of clinical research, Periman Eye Institute, Seattle, Wash

John Sheppard, MD, president, Virginia Eye Consultants, Norfolk, Va.