Coronavirus and Ophthalmology

Coronaviruses (CoV) belong to a large subfamily Coronavirinae, in the family Coronaviridae of the order Nidovirales. These viruses cause illnesses ranging from common cold to more severe diseases such as Middle East Respiratory Syndrome (MERS-CoV) and Severe Acute Respiratory Syndrome (SARS-CoV).

There are four known genera of CoV:

Alphacoronavirus, Betacoronavirus, Gammacoronavirus and Deltacoronavirus.

CoV is a single positive-sense RNA virus. Mutation rates of RNA viruses are greater than DNA viruses, which probably help in a more efficient adaptation process for survival. This makes development of vaccines against such viruses difficult.

COVID-19 is a new strain never reported in humans previously. It was first detected in Wuhan city, China in December 2019. Subsequently, it has spread all over the globe, especially to hot-spots such as Italy and Iran.

Coronaviruses are zoonotic, implying transmission between animals and people.

Current available evidence is that the COVID-19 virus is transmitted between people through close contact and droplets. People most at risk of infection are those who are in contact with a COVID-19 patient and/or who care for COVID-19 patients. This inevitably places health workers at a high risk of infection.

It also could be spread if people touch an object or surface with virus present from an infected person, and then touch their mouth, nose or eyes. Viral RNA has also been found in stool samples from infected patients, raising the possibility of transmission through the fecal/oral route.

Common signs of infection include respiratory symptoms, fever, cough, shortness of breath and breathing difficulties. In more severe cases, infection can cause pneumonia, severe acute respiratory syndrome, kidney failure and even death. Symptoms can appear within 2-14 days after exposure.

WHO has defined four transmission scenarios for COVID-19:

1. Countries with no cases (No cases);
2. Countries with 1 or more cases, imported or locally detected (Sporadic cases);
3. Countries experiencing cases clusters in time, geographic location and/or common exposure (Clusters of cases);
4. Countries experiencing larger outbreaks of local transmission (Community transmission).

Looking at the world-wide spread of disease, WHO officially declared the COVID-19 outbreak as a pandemic on March 11, 2020.

CoV and ophthalmology:

There are a few considerations regarding CoV infection and ophthalmic practice. Firstly, ophthalmologists have to perform examination of the patient from close proximity. Of particular concern is the closeness of the patient to the ophthalmologist during slit lamp microscope examination. Droplets from a cough or sneeze can travel up to 6 m, a range that falls within the distance between patient and ophthalmologist.

Secondly, during the SARS-CoV epidemic, clinical reports have suggested tears as a medium of infection. In a case series by Loon et al., it was shown that viral RNA of the SARS-CoV can be detected by reverse-transcription polymerase chain reaction (RT-PCR) from the tears of infected individuals.

Several reports suggest the virus can cause conjunctivitis and possibly be transmitted by aerosol contact with conjunctiva.

Patients who present to ophthalmologists for conjunctivitis and also have fever and respiratory symptoms including cough and shortness of breath, and who have recently traveled internationally, particularly to areas with known outbreaks (China, Iran, Italy, Japan, and South Korea), or with family members recently back from one of these countries, could represent cases of COVID-19.

The American Academy of Ophthalmogy recommends protection for the mouth, nose and eyes when caring for patients potentially infected with SARS-CoV-2.

The virus that causes COVID-19 is very likely susceptible to the same alcohol- and bleach-based disinfectants that ophthalmologists commonly use to disinfect ophthalmic instruments and office furniture. To prevent SARS-CoV-2 transmission, the same disinfection practices already used to prevent office-based spread of other viral pathogens are recommended before and after every patient encounter.

Applanation tonometers heads should be wiped with sterilization swabs or solutions after examining every patient.

Gloves should be worn when examining any suspected patient.

One should avoid opening or closing doors with hands but rather use elbows, also avoid holding onto railings of stairs. As far as possible social distance should be practiced. Avoid lifts (elevators), cafeterias and other areas where a significant number of people might be present.

Protection of mouth, nose (e.g., an N-95 mask) and eyes (e.g., goggles or shield) is recommended when caring for patients potentially infected with COVID-19. In addition, slit-lamp breath shields are helpful for protecting both health care workers and patients from respiratory illness.

A simple technique to make breath shields from plastic file folders is available at the following link: https://www.youtube.com/watch?v=pXm624pBDUM

Questions ophthalmologists should ask  to identify patients with possible exposure to CoV=

• Does your patient have fever or respiratory symptoms?
• Has your patient or their family members traveled recently? Red flags include international travel to countries such as China, Iran, Italy, Japan and South Korea, and domestic travel to states with high numbers of infected patients.

Recommended protocols when scheduling or seeing patients

• When phoning about visit reminders, ask to reschedule appointments for patients with non-urgent ophthalmic problems who have respiratory illness, fever or returned from a high-risk area within the past 2 weeks.
• If the office setup permits, patients who come to an appointment should be asked prior to entering the waiting room about respiratory illness and whether they or a family member have traveled to a high-risk area in the past 14 days. If they answer yes to either question, they should be sent home and told to speak to their primary care physician.
• Keep the waiting room as empty as possible, and as much as prudent, reduce the visits of the most vulnerable patients.

IMPORTANT LINKS:

https://www.who.int/emergencies/diseases/novel-coronavirus-2019/technical-guidance/infection-prevention-and-control

https://www.who.int/emergencies/diseases/novel-coronavirus-2019

https://www.aao.org/headline/alert-important-coronavirus-context