Dry eye syndrome is caused by a chronic lack of sufficient lubrication and moisture on the surface of the eye.

Its consequences range from subtle but constant irritation to inflammation of the anterior (front) tissues of the eye.

Dry eyes also are described by the medical term, keratitis sicca, which generally means decreased quality or quantity of tears. Keratoconjunctivitis sicca refers to eye dryness affecting both the cornea and the conjunctiva.

Persistent dryness, scratchiness, red eyes and a burning sensation are common symptoms of dry eyes. These symptoms alone may prompt your eye doctor to diagnose dry eye syndrome.

Dry eyes can become red and irritated, causing a feeling of scratchiness.

But sometimes your eye doctor may want to measure the amount of tears in your eyes. A thin strip of filter paper placed under the lower eyelid, called a Schirmer test, is one way to measure tear production.

Another symptom of dry eyes is a "foreign body sensation," which is a feeling that something is in your eye.

And it may seem odd, but dry eye syndrome also can cause watery eyes. This is because dryness on the eye's surface sometimes will overstimulate production of the watery component of your tears as a protective mechanism.

From: www.allaboutvision.com