Tears

 

Hi everyone, last week we looked at light & dark connected with the eyes, this week we are looking at tears. Did you know tears are produced all the time and not just when we cry, this is because they help to keep our eyes moist and clean.

Tears are produced via special glands under the eyelids, called the lacrimal gland which is around the size and shape of an almond these glands produce about 1 millilitre of lacrimal fluid aka tears each day and they drain away via our nasal cavity.

What do tears actually do, well they have four main functions they wash dirt of the surface of the eyeball; they keep the surface of the eyeball clean and moist. They carry water and nutrients to the cornea and lens, lastly, they help prevent infection, as our tears are made up of a watery solution that contain salt, mucus and an enzyme called lysozyme and it is lysozyme that kills bacteria which prevents infection.

Sometimes we produce more tears than the drainage system can cope with such when we are crying or having an allergic reaction which is one reason, we feel the need to blow our nose.

Our eyes produce more tears in response to emergencies such as in response to fumes from an onion or when a foreign object is in the eye.

Some people wonder why their eyes sting when they go to an indoor swimming pool this is because the disinfectants used to keep the pool clean contain chlorine.

Did you know that the ability to express emotions such as extreme happiness or extreme sadness as well as pain or shock by crying is thought to be a uniquely human trait.