The purpose of this paper is to explore in deep detail epidemiology research study methods to research epidemiology problems. The considered epidemiological problem is the ophthalmic manifestations of coronavirus disease 2019. With the spread of COVID-19, numerous people became under the threat of acute respiratory illness, which can cause serious complications and several other diseases. Now, when the virus has been found in tears, there is a significant risk that tears and conjunctival sections, in addition to airborne droplets and direct contact may transmit the coronavirus disease. Although ophthalmic manifestations of coronavirus disease 2019 are rare, there is a risk of conjunctivitis as one of the symptoms of coronavirus disease. The following research and literature review are destined to conduct the statistical analysis and investigate the information on the given epidemiology problem.
The most vulnerable to the coronavirus infection remain healthcare workers, who constantly deal with covid patients. They need to observe all sanitary precautions. Despite the fact, that conjunctiva is not the most commonplace coronavirus infection, having protective equipment on the eyes can still prevent infection. Research from Olson et al. (2020) is shown that only 1% of Canadian healthcare workers who wore protective eyewear were infected while caring for SARS patients while 8% were infected that did not wear eye protection. The given statistic proves the presence of ophthalmic manifestations of coronavirus disease 2019. According to Guan et al. (2020), conjunctival congestion is identified in nine of 1099 (0.8%) COVID-19- positive patients. Conjunctivitis rests the most spread sign of the presence of COVID-19 infection. A meta-analysis including six studies showed that the overall pooled prevalence of ocular manifestations among COVID-19-infected patients was 5.5% (Ulhaq & Soraya, 2020). According to the above-mentioned statistics, unprotected eyes might cause coronavirus infection.
Different methods of researching the subject of ocular manifestation of SARS-CoV-2 RNA are implied. Relevant ocular symptoms data is obtained by communicating with COVID-19- positive patients. Fifteen subjects (27%) reported ocular symptoms in the course of COVID-19, including sore eyes, itching, foreign body sensation, tearing, redness, dry eyes, eye secretions, and floaters (Hong et al., 2020). Some of the patients interviewed claimed that they discovered ocular symptoms before the fever or respiratory ones. In addition, a further three subjects claimed to have worn face masks (without eye protection) during close contact with confirmed COVID-19 cases but were nevertheless still infected (Hong et al., 2020). The conducted investigation once again proves the importance of protecting the ocular surface. The research of Hong et al. (2020) shows that the age of subjects spanned from 24 to 68 years and that the SARS-CoV-2 virus infected both young and older people. There was neither no gender segregation in the research conducted.
Additional evidence that supports the possibility of getting the COVID-19 infection via the eye surface is the case of Dr. Wang Guangfa, a respiratory specialist who investigated the epidemic situation in Wuhan. According to Hong et al. (2020), the doctor contacted COVID-19 and, upon reflection, shared his view that the infection was probably via the eye as he had taken all the usual precautions including wearing an N95 mask during site visits to fever clinics and wards but did not wear any eye protection. He later reported the development of conjunctivitis in the left eye, followed by fever and catarrh.
Moreover, COVID-19 infection may also affect the overall health and condition of the conjunctiva. The micro-environment of the ocular surface and the stability of the tear film could be adversely affected by a generalized systemic immune system reaction to the respiratory infection by the SARS-CoV-2 virus (Hong et al., 2020). This is the way how the coronavirus may infect the ocular tissues and cause the above-mentioned symptoms.
The severity of ophthalmic manifestations of coronavirus disease is rather heterogeneous. Some COVID-19-positive patients may report only eye itching and redness. According to Olson et al. (2020), cases of significant inflammation of the tarsal conjunctiva and hemorrhagic pseudomembranous conjunctivitis with petechiae and tarsal hemorrhages have been reported. Although the COVID-19 ocular presentation is rare and uncommon enough, it should be treated carefully and cautiously. Multiple cases report detailed accounts of patients presenting to the ophthalmologist with conjunctivitis and no other symptoms of COVID-19 infection that were later found to be COVID-19 positive on PCR testing (Olson et al., 2020). The above-mentioned data emphasize the relevance and importance of eye zone appropriate protection.
Although the most commonly observed symptoms of coronavirus are fever, dry cough, and fatigue, there is always a risk that the disease may manifest itself with completely different symptoms. The research of Olson et al. (2020) shows that ocular findings may be the only manifestation of systemic COVID-19 infection, and eye care professionals run the risk of not only becoming infected but also infecting many patients in a high-risk population. Thereby, timely delivery of a PCR test when itching, tearing, redness or dry eyes are detected might prevent the spread of coronavirus within the population.
Moreover, invasion of COVID-19 infection on the conjunctiva may not always signify ocular affection. Hong et al. (2020) claim that viral particles landing on the tear film would be flushed away from the ocular surface relatively quickly and drained into the nasopharyngeal space, where the environment is more conducive to virus invasion. Therefore, tears should be considered carriers of SARS-CoV-2. The novel coronavirus RNA was also detected in tears and conjunctival samples from the infected individual (Xia et al. 2020). However, it is rather important to emphasize that the presence of conjunctivitis disease is an important factor in the detection of viral RNA in tears or conjunctival secretions. Depending on the research of Xia et al. (2020), while taking the tear fluid sample for testing, researchers obtained sputum samples from patients as control samples; 55 of the 60 sputum samples yielded positive results. The conducted research indicates that the tear and conjunctival secretions of patients without conjunctivitis may not transmit the coronavirus infection.
The possibility that patients with severe acute respiratory diseases are more vulnerable to the ocular manifestation of COVID-19 infection exists. Severe infections often require supplemental oxygen or breathing support, which may lead to the redirection of oral secretions or droplets toward the eyes with poorly fitting ventilation masks (Olson et al., 2020). Thus, the patients may spread viral molecules around the eyes, which may result in the virus invasion.
With the worldwide spread of COVID-19 infection, scientists and clinicians from all over the world are actively seeking potential treatments for coronavirus infection. Scientists are conducting research and analyzing already existing treatments for acute respiratory disease. Approximately 30% of these studies are being conducted in China, the original epicenter of this infection and almost 20% are being conducted in the United States (Olson et al., 2020). Currently, dozens of countries are involved in researching and inventing treatments for SARS-CoV-2. Interferon therapy is a unique, cytokine-based treatment with antiviral and immunomodulatory properties that have been used effectively to treat chronic viral infections and autoimmune diseases. Despite the effectiveness of the use of interferon, several ocular complications can be associated with it. The most substantial interferon-induced ocular side-effect involves the eye retina. The reported incidence of interferon retinopathy is quite variable, ranging from 18 to 86%, depending on the initial dose of treatment (Olson et al., 2020). Systemic interferon treatment might provoke microvascular changes in the retina.
In addition to interferon therapy, other methods of COVID-19 treatments are being considered. According to the research of Olson et al. (2020), a few antimalarial treatments are currently being studied for potential therapeutic effects versus SARS- CoV-2. The antimalarial treatment has an inhibitory effect on the fusion of the virus with the host cell. However, this method remains controversial due to the difference in the results of the research conducted regarding the benefits of the approach. Furthermore, chloroquine and hydroxychloroquine may cause several ocular complications and side effects. While corneal verticillata and cataract formation have been reported, the most serious complication is irreversible toxic retinopathy with parafoveal damage, known commonly as, ‘bull’s-eye maculopathy’ (Olson et al., 2020). However, the above-mentioned side effects are the result of the treatment’s chronic overuse or excessively high doses.
A significant number of specialists are seeking additional SARS- CoV-2 treatment. Antiviral agents, for instance, are an alternative treatment for COVID-19 infection. Beigel et al. (2020) conducted a double-blind, randomized, placebo-controlled trial of intravenous remdesivir in adults hospitalized with Covid-19 with evidence of lower respiratory tract involvement. The study aimed to investigate methods of reducing the rehabilitation time for patients with acute respiratory disease. Patients were randomly assigned to receive either remdesivir (200 mg loading dose on day 1, followed by 100 mg daily for up to 9 additional days) or placebo for up to 10 days (Beigel et al., 2020). As a result of the study, remdesivir outperformed placebo in terms of patient recovery time. According to the literature data, uveitis has been reported as a complication in some antiviral agents (Olson et al., 2020).
Another treatment that is being studied by clinicians is plasma-based therapy. The use of plasma from patients who have recovered from COVID-19 has the potential benefit of providing disease-specific neutralizing antibodies before targeted therapies can be developed (Lythgoe & Middleton, 2020). Since the given practice is still being studied by scientists, no information has been recorded regarding any ocular complications caused by plasma-based therapy.
Considering the risks of ocular complications that the above-mentioned treatments might cause, the vaccine may become an alternative treatment for SARS- CoV-2. The COVID-19 vaccine is a synthetic gene that has been used to modify antigen-presenting cells and is thought to confer immunity upon injection (Olson et al., 2020). Moreover, no ocular complications nor side effects have been reported at the moment. Several vaccines are currently being studied by scientists all over the world.
Summarizing the above literature review and conducted research, it may be argued that COVID-19 infection is dangerous and unpredictable enough. Ocular manifestations in COVID-19 are rare enough, though the conjunctiva remains vulnerable to SARS- CoV-2 and requires appropriate protection as well as treatment. The tears may both ensure getting of coronavirus infection into the conjunctiva and transmit it into the nasopharyngeal space. Sore eyes, itching, redness, and dry eyes should be considered cautiously, as they might indicate the coronavirus invasion. According to the conducted research, vaccination may be the most suitable method of treating coronavirus at the moment since it does not entail any ocular complications. All the above-mentioned factors may be crucial in preventing the spread of COVID-19 disease.
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