What kinds of problems do people get with their tears?
The tear system of the eye normally keeps the eye wet enough to be comfortable without overflowing. But some people's eyes are too dry, while others are too wet.
Dry eye syndrome is what doctors call the condition when an eye is not being kept wet enough to be comfortable. There are several causes of dry eye syndrome, and more information is available in the "Dry Eye Syndrome" fact sheet from the Cole Eye Institute. Other times the tear system makes the eye too wet.
How can the tear system make the eye "too wet"?
There are three main parts in the tear system: (1) the glands that make the tear fluid; (2) the openings that let tears flow out of the eye; and (3) the ducts inside the nose that tears drain through. Each has a different function and a problem with any of them can lead to excess tears.
How do the tear glands normally work, and what problems can happen when they are not working properly?
The lacrimal glands underneath the skin of the upper eyelids make a fluid that is mostly salt and water. This salty water gets to the eye through small openings inside the upper eyelids. When the eyelid blinks, the watery liquid is spread across the eye. There are other glands on edges of the eyelids that make oils. The most important of these glands are called the meibomian glands.
The oils from these glands actually float on top of the watery fluid in the tears. This keeps the water from evaporating too quickly. Some of the oils stay along the edge of the eyelid, and they help keep the tears from "leaking" over the eyelashes. If there is not enough of these oils, tears will keep overflowing from the eyes. Oddly enough, a problem with the meibomian glands can lead to overflowing tears and dry eye syndrome at the same time!
This happens when the lacrimal glands make enough salt-watery fluid to cover the eye, but the meibomian glands do not make enough oils. The surface of the eye actually dries out between blinks. This makes the eye irritated, and the lacrimal glands make even more fluid. But this fluid just overflows from the eye instead of keeping it wet.
This is one form of epiphora, which is the medical term for the condition of overflowing tears. There are several other possible causes of epiphora. The lacrimal glands might be making too much fluid because the eye is irritated by wind, bright light, dust or allergies. The other causes of epiphora are related to problems with the drainage system of the eye.
How does the tear drainage system normally work, and what can go wrong with it?
There are small openings inside the edges of the eyelids near the nose. Each upper and lower eyelid has one of these openings, called a punctum. These four openings, or puncta, act like little valves to take tears out of the eye. Each time we blink, some tear fluid is pumped out of the eye through the puncta.
If some or all of the puncta are blocked, tears will overflow. The puncta are tiny, so they can be blocked by small particles of dirt or even loose cells from the skin around the eye. Sometimes an infection near the puncta will make the area swollen, and the puncta will not work properly. Any of these things can cause epiphora.
How do the tear drainage ducts normally work? What can go wrong with them?
After the tears leave the eye through the puncta, they drain down through a little "tube" called the nasolacrimal duct. This duct goes underneath the skin and through the bones of the face into the nose. Normally, there is so little tear fluid that the nose does not get very wet. The connection between the eye and the nose is obvious, however, when someone is crying.
Even when the puncta are open and working well, the nasolacrimal duct can be blocked. Not only will this cause problems with tear drainage, it usually has other symptoms too, including:
- Swelling and redness in the area between the eye and the nose.
- Pain in the area around the eye and nose.
If the nasolacrimal duct is blocked, it can become infected. This is called dacryocystitis, and it can become very uncomfortable.
How can excessive tearing be treated?
Only a doctor can recommend the right treatment for someone with tearing problems.
It is not unusual for newborn babies to have excessive tearing due to insufficient drainage of the tears. More information about this problem is available in the fact sheet on "Tear Duct Obstruction in Children" from the Cole Eye Institute.
In older patients with overflowing tears, the doctor will examine the eye carefully. If the tearing problem seems to be related to dry eye syndrome, there are several treatment options (see the "Dry Eye" fact sheet). If the problem is related to allergy or other irritation of the eye, then treating the irritation will reduce excessive tearing.
In other cases, it will be necessary to perform a special test to make sure fluid can pass through the puncta and nasolacrimal duct.
What if part of the tear drainage system is blocked?
If the test shows that tears cannot get through a punctum, the doctor might recommend placing a warm, wet, clean washcloth on the eye a few times a day. This could help open up the blocked punctum and let any fluid inside drain out. Your doctor will explain exactly how to do this and how many times a day it should be done. This can open the punctum in just a few days, or it might take longer.
Your doctor might recommend a procedure to open a blocked punctum. He or she can do this right in the office by numbing the eye with anesthetic, then passing a special instrument through the punctum. This might be necessary if the nasolacrimal duct seems to be infected. The doctor will probably prescribe antibiotics if there seems to be an infection.
Sometimes an infection will have the side effect of blocking the nasolacrimal duct permanently. This is a problem for two reasons. Not only will the eye keep overflowing with tears, the blocked nasolacrimal duct will keep on getting infected. Fortunately, there is a procedure to fix this problem.
Dacryocystorhinostomy is the complicated medical name for an operation to make a new tear drainage system for the eye.
This operation may be done under general anesthesia (with the patient "asleep") or with local anesthesia (the patient is awake but does not feel the pain). The surgeon will make an incision near the nose. A small plastic tube is connected to the tear duct near the eye, and the other end opens into the nose. The plastic device keeps the new drainage system open while the eye heals. After a few months, the tube is removed. This technique is very effective at solving the problem of overflowing tears due to nasolacrimal duct blockage.