Tears are produced by the lacrimal gland located in the upper outer portion of each eye.
They normally drain from the eye through small tubes called tear ducts or nasolacrimal ducts( NLD) that stretch from the eye into the nose. A blocked tear duct occurs when the opening of the duct that normally allows tears to drain from the eyes is obstructed or fails to open properly. If a tear duct remains blocked, the tear duct sac fills with fluid and may become swollen and inflamed, and sometimes infected.
What causes a NLD Block ?
n babies, the most common cause of NLD Block is the failure of the thin tissue at the end of the tear duct to open normally.
Other less common causes of NLD Block in children include:
Infections.
Abnormal growth of the nasal bone that puts pressure on a tear duct and closes it off.
Closed or undeveloped openings in the corners of the eyes (puncta) where tears drain into the tear ducts.
In adults, tear ducts may become blocked as a result of a thickening of the tear duct lining, nasal or sinus problems, injuries to the bone and tissues around the eyes (such as the cheekbones), infections, or abnormal growths such as tumors.
What are the symptoms?
Usually, the first symptom of NLD Block is excessive tearing, ranging from a wet appearance of the eye to tears running down the cheek. Babies who have blocked NLD usually have symptoms within the first few days to the first few weeks after birth. If infection occurs in the eye's drainage system , you may see redness and swelling (inflammation) around the eye or nose. Also, yellow mucus can build up in the corner of the eye, and the eyelids may stick together. In severe cases, infection can spread to the eyelids and the area around the eye.
The symptoms of a blocked tear duct may get worse after an upper respiratory infection, such as a cold or sinus infection. Also, symptoms may be more noticeable after exposure to wind, cold, and sunlight.
How is NLD Block diagnosed?
A blocked tear duct is diagnosed based on a medical history and a physical exam. Also, tests may be used to measure the amount of tears or to see whether tears are draining normally from the eyes. Other tests can help your doctor find out where the blockage is or how it was caused
Diagnosis
Diagnosis is based on symptoms. The cause of the tear duct blockage must also be identified. Tests are determined by the patient's age and symptoms. To determine the presence and extent of tear duct blockage, a fluorescein eye stain is used to observe the drainage of tears. An orange dye is placed in the eye using a dropper or blotting paper. After it covers the surface of the cornea, a blue light is shone on the eye to detect abnormalities on the cornea, including delays in tear drainage.
An internal examination of the nose may be indicated, especially if an injury has occurred. Imaging tests and x-rays also may be warranted to rule out other causes, such as a tumor. In adults, a fluid is irrigated through the nasolacrimal drainage system to locate and determine the extent of the blockage.
Treatment
Treatment depends on the symptoms, the cause, and the age of the patient. If an infection is present, it is treated first. Antibiotic eye drops or ointment are usually prescribed.
A blocked duct in an infant is treated by gently massaging the area between the eye and nose several times a day. This treatment is usually successful in opening a blockage or helping to move a blockage that is in the process of self-resolving. If tearing is persistent beyond 1 year of age or if the affected eye is infected, a surgical procedure is performed.
In adults, the cause of the blockage must be determined. If an infection clears and the duct remains obstructed, or if an infection recurs, further treatment may be necessary. In children and adults, a duct can sometimes be reopened by placing a small probe into the duct. If this does not remove the obstruction, a silicone tube can be inserted to maintain an opening. In children, the tube usually must remain in position for 6 to 12 months, until the tear duct stays open by itself. The drawback to this method is that a second procedure may be necessary to remove them.
Surgery
If conservative measures fail, patients may require a procedure called dacryocystorhinostomy, the creation of a new passage for tears to flow. This is performed in a hospital, under general anesthesia. The procedure is more than 90% successful in relieving the blockage.
If the tear duct is damaged beyond repair due to chronic infection or injury, an artificial duct can be surgically implanted. The artificial tear duct, called a Jones tube, is placed behind the inner corner of the eyelid to drain tears into the nose.
Tumors or nasal polyps that cause obstruction usually are removed surgically.
Prevention
In many cases, tear duct obstruction cannot be prevented. Safety precautions should be taken when playing contact sports and performing other types of physical activities (e.g., wearing helmets and face masks) to prevent trauma to the face. Prompt and adequate treatment for nasal and eye infections may also reduce the risk.
