Not having enough tears (dry eye) is caused by a lack of one or more of the substances that make up tears.
Dry eyes are common in those who wear contact lenses. They affect some soft-lens wearers and many hard-lens wearers. Eye diseases and other diseases and certain medicines can cause dry eyes.
Symptoms of dry eyes include:
Symptoms may get worse at the end of the day and in drafty, dry, smoky, or dusty environments.
Dry eye may also cause a type of keratitis (inflammation of the cornea). Changes in the type of contact lens and the way the lens sits on the eye may help correct this problem.
Corneal drying (desiccation) affects some people who wear soft contact lenses. Soft lenses absorb water from the eye surface, making the eye drier. Desiccation causes patchy loss of cells in the cornea. Changing to a different type of lens can sometimes help the problem.
WebMD Medical Reference from Healthwise