MICROANATOMY

Detailed explanation-1: -Chemical barriers against infection include enzymes in tears, saliva and mucus that break down the surface of bacteria. The acid in sweat and in the stomach kills cellular pathogens and there are anti-bacterial proteins in semen (the fluid that contains male sperm).

Detailed explanation-2: -Foreign bodies that enter the eye are washed out by tears. Moreover, tears contain a substance called lysozyme, which has an antibacterial action, and works to prevent invasion and infection by microbes.

Detailed explanation-3: -The tear fluid creates a chemical barrier at the surface of the eye as part of the innate immune system, which provides protection against pathogens by secreting antibacterial and immunomodulatory proteins (AMPs) that inhibit bacterial growth [28].