What is epiphora?
Epiphora is a condition characterized by excessive eye watering. The condition is fairly common and may affect one or both eyes. Lacrimation, also known as “tear production,” is a natural process performed by the eyes to keep them clean, clear and healthy.
Types of tears
There are different types of tears that provide various functions for the eyes. These include emotional tears, basal tears, reflex tears and crocodile tears (also called hyperlacrimation).
Basal tears are constantly produced by the eyes as a way to clean and protect the cornea. Typically, the eyes produce 1.2 microliters of basal tears per minute — less than one teaspoon per day.
Emotional tears are produced in response to strong — you guessed it — emotions, while reflex tears are produced when the eye is irritated, injured or in pain. Hyperlacrimation is a rare condition in which the facial nerve is injured and, after healing, mistakenly activates the tear gland.
These three types of tears can be produced in large quantities up to one hundred times more than basal tears.
Once tears are produced, they spread over the surface of the eye, which can hold up to eight microliters of tears at any given time. Tears then leave the surface of the eye through small drainage channels in the eyelids called canaliculi at a rate of about 0.6 microliter per minute.
These tears are deposited in the back of the throat. Some of the tears will evaporate from the surface of the eye as well.
A key symptom of epiphora is tears spilling out onto the cheeks. This is because the volume of tears is too much for the eyes’ surface to hold.
Someone with epiphora would produce more than eight microliters of tears at any given time, either by making too many tears or by draining too few tears. Your eye doctor can use different tests to determine which of these two is the cause of epiphora or whether it's a combination of the two.
Babies under 12 months and adults over age 60 are more prone to epiphora. In babies, this is usually caused by a blocked tear duct, while in older adults it can also be from an overproduction of tears.
Minor cases of epiphora may not need medical intervention. However, there are treatments available that can help.
SEE RELATED: What are tears made of?
Symptoms of epiphora
The main symptom of epiphora is excessive eye watering. Your eyes may feel overly moist, and tears may pool in your eyes, which can blur vision. It’s also possible for tears to spill onto your cheeks, even though you’re not crying.
