Protections of the eye:
The human eye is one of the most important things to a person and thus has many forms of protection.
The eyelid protects the eye in three different ways: the eyelashes, the glands, and the movement of the eyelids.
The eyelashes are beneficial in keeping dust and debris out of the eye. Touching the lashes will trigger the reflexive blinking mechanism.
There are many different glands that are located in the eye. The Zeis gland is a gland that secretes oil. An infection in this gland results in a stye. A second gland, the Meibomian gland, are large oil secreting glands located in the lid of the eye and play a part in producing the oily outer layer of tears. This oily layer prevents the evaporation of tears. Also contributing to the make up of tears are the aqueous and mucous producing glands.
Eyelids protect the eye mainly by their rapid rate at which they cover the eye. Even though blinking interrupts the line of vision, the illusion of sight continues while the eye is briefly closed.