Dry eye is a common medical condition and is caused by a problem with the drainage, evaporation or production of tears. Tears are moved across the eye when you blink to lubricate the front surface of your eye, wash away debris, protect against infection and to help stabilize vision.
Tears are made up of three main components: an outer lipid layer which prevents tears from evaporating and eyelids from sticking together, a middle watery layer which carries nutrients and oxygen, and an inner mucous layer which allows the tears to wet the cornea. Each layer is produced by different glands in and around the eyelids.
It is possible to be diagnosed with dry eye even if you have very watery eyes; this can be due to a problem with one of the other layers of the tears. Dry eye can usually be easily managed.