Conjunctiva
The conjunctiva is a membrane that lines the inside of the eyelids and extends over the front of the white part of the eye. It produces mucus, a clear viscous fluid that lubricates the eyeball, as well as some tears, which help keep the eye clean. Most tears, however, are produced by the lacrimal glands. A lacrimal gland lies at the upper outer corner of each orbit and spreads a smooth layer of mucus and tears over the eye each time a person blinks. After a person blinks, the fluid spreads evenly over the eye then flows into tiny canals in the lids. These canals lead to the lacrimal sac, a pouch at the lower inner corner of each orbit. From the lacrimal sac, the mucus and tears drain through a passage into the nose.