EVERYDAY SCIENCE

Detailed explanation-1: -The tear glands (lacrimal glands), located above each eyeball, continuously supply tear fluid that’s wiped across the surface of your eye each time you blink your eyes. Excess fluid drains through the tear ducts into the nose.

Detailed explanation-2: -The lacrimal glands underneath the skin of the upper eyelids make a fluid that is mostly salt and water. This salty water gets to the eye through small openings inside the upper eyelids. When the eyelid blinks, the watery liquid is spread across the eye. There are other glands on edges of the eyelids that make oils.

Detailed explanation-3: -When blinked, the eyelids help spread tears evenly over the surface of the eye. Tears consist of a salty fluid that continuously bathes the surface of the eye to keep it moist and transfers oxygen and nutrients to the cornea, which lacks the blood vessels that supply these substances to other tissues.

Detailed explanation-4: -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. Tears contain components that heal damage to the surface of the eye.