Watery eyes, medically known as epiphora, is a condition in which the eye produces an excess amount of tears. While this condition is not usually serious, it has a variety of causes and may sometimes indicate the need for corrective surgery.
Environmental factors are perhaps the most common cause of watery eyes. This category includes things as simple as an onion to pollution, smog, smoke, dust, allergies and the presence of harmful chemicals in the air. Watery eyes may also be caused by irritation or injury to the eye, such as a scratch or other damage.
Watery eyes can actually be a symptom of dry eyes. In this case, the irritation of dry eyes causes the tear ducts to overcompensate and produce more tears than necessary. The result is constant tearing that often masks the original problem of dryness in the eyes.
A condition known as blepharitis (inflamed eyelids) sometimes prevents the lower lids from producing the substance that allows tears to spread smoothly over the entire eye. Because of this, tears spread unevenly across the eye, leaving areas of the eye unprotected from the open air. This may also be a cause of excessive watering.
Problems with the lower eyelid may also cause the eyes to water. One of these, known as ectropion, occurs when the lower lid is too relaxed, causing it to droop and expose the inside of the lower lid. The opposite condition, called entropion, occurs when the lower eyelid is stretched too tightly, causing the lower lashes to curl inside and grow under the lid. Both of these conditions can be corrected with a minor outpatient surgery.
Tears normally are produced in the upper lid near the outer corner of the eye. They travel across the eye to the inner corner and enter a small duct that drains tears into the nose. However, if the naso-lacrimal duct become clogged or infected, moisture in the eyes that would typically go unnoticed overflows and makes the eyes watery.
Conjunctivitis (pink eye) and other similar infections may cause temporary watering in the eyes. The watering should go away after the condition has been treated by a doctor.
Watery eyes are not usually a serious condition, but you should contact a doctor if you experience prolonged, unexplained tearing, unusual discharge or consistent pain in the eyeball or sinuses.