Watering eye, epiphora or tearing, is a condition in which there is an overflow of tears onto the face, often without a clear explanation.
There is insufficient tear film drainage from the eye or eyes. Instead of the tears draining through the nasolacrimal system, they overflow onto the face.
Tears are needed to keep the front surface of the eye healthy and maintain clear vision, but too many tears can make it difficult to see. This can make driving difficult or dangerous.
Epiphora can develop at any age, but it is more common in those aged under 12 months or over 60 years. It may affect one or both eyes.
Watering eye can usually be treated effectively.
The two main causes of watering eyes are blocked tear ducts and excessive production of tears.
Blocked tear ducts
Blocked ducts are the most common cause of watering eyes in adults.
Some people are born with underdeveloped tear ducts. Newborns often have watery eyes that clear up within a few weeks, as the ducts develop.
The most common cause of watering eyes among adults and older children is blocked ducts or ducts that are too narrow. Narrowed tear ducts usually become so as a result of swelling, or inflammation.
If the tear ducts are narrowed or blocked, the tears will not be able to drain away and will build up in the tear sac.
Stagnant tears in the tear sac increase the risk of infection, and the eye will produce a sticky liquid, making the problem worse. Infection can also lead to inflammation on the side of the nose, next to the eye.
Narrow drainage channels on the insides of the eyes (canaliculi) can become blocked. This is caused by swelling or scarring.
Over-production of tears
Irritated eyes may produce more tears than normal as the body tries to rinse the irritant away.
The following irritants can cause the over-production of tears:
some chemicals, such as fumes, and even onions
an injury to the eye, such as a scratch or a bit of grit (tiny pebble or piece of dirt)
trichiasis, where eyelashes grow inward
ectropion, when the lower eyelid turns outward
Some people have tears with a high fat, or lipid, content. This may interfere with the even spread of liquid across the eye, leaving dry patches which become sore, irritated and cause the eye to produce more tears.
There are many causes of watering eyes. The following conditions among others can also lead to an overflow of tears:
keratitis, an infection of the cornea
corneal ulcer, an open sore that forms on the eye
styes or chalazions, lumps that can grow on the edge of the eyelid
allergies, including hay fever
a problem with glands in the eyelids called the Meibomian glands
use of certain medications