**2. Physiopathology**

There are some theories proposed to explain the pathophysiology of viral inoculation into the human conjunctiva. The main ones are direct inoculation of infected droplets on the ocular surface (cornea and conjunctiva); migration of the virus from the upper respiratory tract through the nasolacrimal duct to the ocular surface; and hematogenous infection of the lacrimal gland. All these theories are based on the presence of the ACE2 receptor, essential for the entry of SARS-CoV2 into human cells, in several structures of the human eye [1–3].

**Figure 1** shows an illustration of the theory of direct inoculation of the virus on the ocular surface by binding to the ACE2 receptor.

SARS-CoV-2 enters the target cells by binding the viral Spike (S) protein to the ACE2 receptor, followed by its initiation by the (TMPRSS2) protein. The ACE2 receptor is present in several organs of the body, including various structures of the human eye such as the cornea, conjunctiva, iris, ciliary body, and aqueous humor.

Note in **Figure 2** this distribution in different tissues of the body.

## **Figure 1.**

*Source: Cortesy by Cunha CEX, 2020. This figure was designed using freepik.com resources (https://br.freepik. com/). The physiopathology illustrated was described by Napoli et al.*

## **Figure 2.**

*Source: Cortesy by Cunha CEX, 2020. This figure was designed using freepik.com resources (https://br.freepik. com/). Distribution of the ACE2 receptor in different tissues of the body as presented by Amesty et al.*
