DISCUSSION
There is suspicion and some evidence that SARS-COV2 invades ocular surfaces. Possible mechanisms such as direct conjunctival contact of infected droplets, hematogenous infection of the lacrimal gland or viral migration from the upper respiratory system have been described for the SARS-COV-2 virus to infect the ophthalmic surface (17). The incidence of conjunctivitis in patients with COVID-19 has been reported as 0.8 and 4.76 percent (18)(19)(20).
In the study conducted by Ping Wu et al., the ocular symptoms of 38 patients who were clinically diagnosed as having COVID-19 and treated as inpatients were questioned, and RT-PCR was performed by taking nasopharyngeal and conjunctival samples. Although SARS-CoV-2 was detected in nasopharyngeal samples in 28 (73.7%) patients, it was shown in conjunctival samples in only 2 (5.2%) patients. However, in 12 of 38 patients (31.6%), symptoms related to conjunctivitis such as conjunctival hyperemia, chemosis, and epiphora were observed. Ocular symptoms were mostly observed in patients with severe pneumonia and the middle stage of the disease (16).
In an epidemiologic study conducted in China on 534 patients who were SARS-CoV-2–positive, 25 (4.68%) patients had conjunctival congestion, and dry eye (112, 20.97%), blurred vision (68, 12.73%), and foreign body sensation (63, 11.80%) were reported as the most common symptoms associated with COVID-19 (21). In another epidemiologic study conducted in a total of 30 hospitals in China, conjunctivitis was found in 9 (0.8%) of 1099 patients who had a positive SARS-CoV-2 test and were hospitalized (22).
In a study from Wuhan, China, conducted by Deng et al., SARS-CoV-2 was detected using RT-PCR in nasopharyngeal samples in 90 (76%) of 114 patients followed up in hospital due to COVID-19 pneumonia, and the virus was not detected in any of the conjunctival samples. In addition, none of the 114 patients had ocular symptoms such as red eyes or pain (23). In another study, five patients with COVID-19 presenting only with symptoms and signs of conjunctivitis were described (24).
In our study, there were 15 (7.44%) patients showing conjunctival inflammatory response who had foreign body sensation, epiphora, and conjunctival congestion symptoms, which were not present prior to the COVID-19 infection. Although more comprehensive studies are needed, our study seems to be compatible with the existing literature. The rate of conjunctivitis or conjunctival inflammatory response has been shown in a wide spectrum in these studies. These spectra were explained by the fact that no biomicroscopy examination was performed on patients in any studies in the literature, and even that the data in most studies were based on patients’ subjective symptoms obtained through teleconferences. During our study, the fact that the patients were seen by an ophthalmologist in person and evaluated with a penlight, although a biomicroscopic examination was not performed, was a positive situation for the safety of our data.
In a meta-analysis evaluating laboratory findings, 5350 patients from 25 studies were included and high levels of CRP, procalcitonin, D-dimer, and ferritin were associated with poor outcomes (25). In another study, it was shown that patients with COVID-19 with ocular symptoms had higher WNC counts, neutrophil counts, and CRP, LDH, and procalcitonin values ​​compared with patients without ocular symptoms (16). In another study, no significant difference was found between patients with and without SARS-CoV 2 virus isolated from the conjunctiva in terms of laboratory findings (26). In our study, when the laboratory data of 234 patients were compared, no significant difference was found between patients with and without ocular symptoms. Our patients had moderate or severe symptoms and were hospitalized patients. Patients with very severe disease in the intensive care unit (ICU) or asymptomatic patients followed up at home were excluded from the study. As far as we know, no other comprehensive studies have investigated the relationship between conjunctivitis and laboratory data in patients with COVID-19.
It was suggested that the ocular surface might be an entry point for SARS-CoV-2, and ocular involvement was less common thanks to the antiviral defense system in the conjunctiva and cornea, as well as lactoferrin and secretory immunoglobulin (Ig)-A (27).
Viruses trigger the immune system, leading to an increase in immunoglobulin, chemokine and antibody production, and cause tissue damage, apoptosis, and inflammation (28).
Ocular findings associated with COVID-19 may be due to viral effects or to dry eye that develops in these patients. There may be several reasons why dry eye occurs in these patients. The first is the prolongation of the time of watching screens following restrictions of social activities in patients. Another reason is that with the use of a mask, the airflow from the mask to the ocular surface evaporates the tears earlier. Indeed, there are some viruses associated with dry eye disease (29). Considering the presence of viruses associated with dry eye disease, it can be thought that the SARS-CoV-2 virus will affect the conjunctival goblet cells or the lacrimal gland through blood, disrupting the tear structure and playing a role in the development of dry eye or conjunctival inflammatory response.
Our study had some limitations. The sample size was relatively small, patients with severe clinical findings in the ICU were not included, and SARS-CoV-2 RT-PCR examinations were not performed on conjunctival samples.
As a result, there was a significant relationship between COVID-19 and an acute conjunctival inflammatory response. Blood parameters that determined progression in patients with COVID-19 were not significant in terms of ocular findings.
Declarations of interest: none