What to know and how to behave is essential to manage both the emergency phase and the gradual return to normal.
SARS-CoV-2
SARS-CoV-2 is a positive-strand RNA virus, belonging to the family of Coronavirus, so called because of its typical crown-like appearance, visible under an electron microscope. From the data on the pandemic's progress, we know that it is highly transmissible and has a high mortality rate, especially in the elderly and those with co-morbidities such as immunosuppression, respiratory disease and diabetes mellitus.
The infection caused by SARS-CoV-2 has been named COVID-19, an acronym derived from COrona VIrus Disease - 2019.
Scientific research is working at a frantic pace to find effective therapies to combat the infection and, above all, a vaccine to prevent it.
But what is the stage of knowledge and what are the most correct ways to manage patients in the ophthalmic field?
Ocular implications of COVID-19
Data published in reports and articles show that SARS-CoV-2 can cause conjunctivitiseither as the first sign of infection, or during hospitalisation for severe forms of COVID-19 pathology.
It is generally a mild form of follicular conjunctivitiswhich is difficult to distinguish from other conjunctival inflammations caused by viruses and most often affects only one eye, causing a faint redness and the sensation of a foreign body. Swelling of the ipsilateral lymph node at the junction of the jaw also usually occurs.
It is therefore possible that SARS-CoV-2 is transmitted to the conjunctiva by aerosol or through hand contact with the eyes.
The presence of SARS-CoV-2 RNA has also been demonstrated at tear fluid and in the eye secretions of virus-positive patients.
This important discovery was announced in the journal Annals of Internal Medicine by researchers at the Spallanzani National Institute for Infectious Diseases in Rome.
The researchers were able to isolate the virus from an eye swab taken three days after admission from a virus-positive patient who was admitted to the Spallanzani hospital at the end of January and had bilateral conjunctivitis, thus demonstrating that it is able to replicate not only in the respiratory system, but also in the conjunctivae.
Spallanzani's research revealed the prolonged persistence of Sars-CoV-2 in the ocular apparatus, even when samples from the respiratory tract no longer showed any traces of the virus: the patient's respiratory samples were negative three weeks after admission, while the ocular sample was still weakly positive up to 27 days after admission.
This is a very important finding, which has in fact also been officially released by the World Health Organisation due to its important public health implications as it shows that the ocular apparatus is a potential route of infection.
Basic rules in the laboratory
– Disinfectant agents: SARS-CoV-2 is sensitive to disinfectants based on alcohol (in solution to at least 70%) and bleach (diluted), commonly used by ophthalmologists to disinfect ophthalmic instruments and laboratory equipment. It is therefore recommended, before and after each visit to implement the disinfection practices already in use to prevent the spread of other viral pathogens.
It is therefore necessary:
- thoroughly disinfect the laboratory and instruments after each visit.
- Wear disposable gloves when cleaning and disinfecting surfaces, discard gloves after one use.
- All patients should be treated with caution: at this stage of the COVID-19 pandemic, practically each patient who undergoes an eye examination may have been infected with SARS-CoV-2, regardless of the presence of a diagnosis, risk factors, reasons for the visit or geographical location.
PPE for ophthalmic use
The need for adequate protection of the mouth, nose and eyes in the course of ophthalmic practice is supported by deaths from COVID among ophthalmologists and ENT specialists in China and Italy, new data on environmental contamination by the virus, and a growing awareness of the spread of infection by asymptomatic or pre-symptomatic persons.
Furthermore, in light of recent findings concerning the presence and persistence of the virus in tear fluid, when visiting or treating patients potentially suffering from COVID-19 is essential to protect mouth and nose with FFP2-type filtering masks for sanitary use and the eyes with goggles, protective visors or breather shields).
Breath guards for slit-lamps at this stage are supplied free of charge by some manufacturers (including Topcon and Zeiss), to accompany the equipment.
Ocular risks of certain anti-COVID19 therapies
Chloroquine and hydroxychloroquine are among the drugs used to combat COVID-19 infection. However, a review published by a working group of the Asia-Pacific Vitreo-Retina Society reported that daily doses, proposed in many ongoing studies worldwide, exceed the maximum daily dose considered safe for long-term therapy of rheumatic and other chronic diseases (typically <5mg/kg of actual weight for hydroxychloroquine).
The risk of irreversible maculopathy for such high doses given even for short periods is unknown.
Patients should, therefore, be informed of the possible macular toxicity before starting therapy. It is also unclear how necessary a baseline fundus examination and/or imaging may be in the case of high doses for a relatively short duration. Additional diagnostic tests, such as ERG, are not recommended for these short-term treatments, not least because performing this type of examination in the current situation would result in exposure to an unnecessary risk of virus transmission. Until there is clarity on the toxicity associated with current treatment regimens, decisions should be made on an individual basis, taking into account any previous retinal disease.
The Internet and the accuracy of information
News, scientific and pseudoscientific, is constantly being published online from sources that are not always reliable and verified.
In this context of 'emergency', also in terms of the quality of information, we would like to point out that the American Academy of Ophthalmology (AAO) is publishing a page dedicated to updates on COVID-19 and relevant information in ophthalmology https://www.aao.org/headline/alert-important-coronavirus-context
The page provides constant updates, every 24 hours.
Dr. Carmelo Chines
Direttore responsabile
English 
Italian