Which mechanism acts as an orbital defense against infection?

The correct answer involves the lubricating effects of blinking, which plays a vital role in the defense of the ocular surface. Blinking not only helps to spread tears evenly across the eye but also assists in removing debris and pathogens that may be present on the surface of the eye. This mechanical action of closing and opening the eyelids contributes to maintaining a healthy tear film that provides lubrication and contains antimicrobial properties.

Additionally, the act of blinking can help flush out foreign particles and microorganisms, reducing the chance of infection. It is this protective mechanics, combined with the constant renewal of the tear film that keeps the eyes clean and helps prevent infection, making the lubricating effects of blinking a significant defense mechanism.

While other mechanisms, such as the production of tears, the presence of immune cells, and the corneal reflex, also contribute to the overall defense against infection, the focus here is on the immediate mechanical advantage provided through the act of blinking itself.