Eye problems and excessive tearing

Tears supply oxygen and nutrition to the cornea and help provide a smooth eye surface. A tearing eye may be a nuisance but usually is not a serious problem. Many people produce extra tears on cold or windy days. This is normal.
Tears:

• Keep the eye moist all the time (baseline tears).
• Wash out the eye when it gets irritated (reflex tears).
• Are related to strong emotions (cry reflex tears).

Excessive tearing in one or both eyes includes tearing that is:

• More than usual for you.
• More in one eye than in the other.
• Like crying, but you have not been crying.

Excessive tears may mean a problem with eye irritation or drainage of the tears. If irritation is causing the extra tears, the cause of the irritation needs to be identified and treated. Drainage problems can be caused by problems with the position of the lower eyelid or by a block in the drainage (tear duct) system.
Allergies may cause the eyes to produce an excessive amount of tears.
Some people with dry eye syndrome (keratoconjunctivitis sicca) complain of tearing too much. Actually, the eye becomes irritated because it does not make enough tears. This irritation causes more tears to be produced.