Introduction
In December 2019, China reported a pneumonia outbreak in Wuhan, a city with more than 11 million people [1]. A new coronavirus (COV) was identified as the causative organism—namely, novel coronavirus, nCOV-Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2)—and the disease was named as the Coronavirus Disease 2019 (COVID-19) [2]. After its introduction, World Health Organization declared the situation as a public health emergency of international concern and published suggestions for protection and prevention of transmission [3].
The first case in Turkey was officially announced on March 11, 2020. To date, COVID-19 has confirmed to affect a total of 115000 patients in Turkey with more than 3000 deaths. Due to the life-threatening nature of its complications, most of the research about COVID-19 mainly focuses on respiratory system. However, since other organ involvements might be alternative routes of transmissions, they must not be ignored.
Seven types of CoVs are known to infect humans: 229E, NL63, OC 43, HKU, MERS-CoV, SARS-CoV, and the recent SARS-CoV-2 [4]. Most of these CoVs cause infections in the respiratory tract but also known to have manifestations in the gastrointestinal system and ocular tissues [5, 6]. HCoV-NL63 and SARS-CoV are known to affect the ocular system. There have been reports of cases with conjunctivitis and bronchiolitis between 2000 and 2003 with HCoV-NL63 [7]. In addition, in 2004, SARS-CoV-RNA was identified in tear samples of three patients suggesting that the virus can be present in tears [5]. Theories, including the conjunctiva being the direct inoculation site of pathogen-loaded droplets, migration of the infection from the respiratory tract through the nasolacrimal duct or even hematogenous infection of the lacrimal gland, were proposed [5].
Genomic and structural analyses show a similar receptor-binding motive between SARS-CoV and SARS-CoV-2 with resembling pathologic features and epidemiological characteristics [8, 9]. As a result, a similar involvement of the ocular tissues has been suspected. Nevertheless, there have only been few reports about the ophthalmic manifestations of the recent SARS-CoV-2 [10, 11]. The purpose of our study is to investigate ocular findings and symptoms of clinically confirmed COVID-19 patients and assess the relationship with those findings and laboratory results.