Nasolacrimal Duct Obstruction
Blocked Tear Duct
The eyeball is kept moist and healthy by a thin film of tears that is continuously produced by the lacrimal gland situated underneath the top eyelid. Every time we blink, tears are swept towards the inside corner of eye and drained through two tiny tubes called lacrimal ducts. From there, tears pass into the nasolacrimal sac, then into the nasolacrimal duct to the nose and, ultimately, to the throat for swallowing. A blockage along any point of this tear duct system is known as a blocked tear duct or dacryostenosis. The symptoms include a pus-like discharge. Some babies are born with a blockage (congenital dacryostenosis). A range of conditions and events, including infection and trauma to the nose, can cause acquired dacryostenosis.
Symptoms
The symptoms of a blocked tear duct can include:
- Watering eye
- Tears running down the face
- Discharge of pus
- Crusted mucus along the eyelashes
- Increased susceptibility to eye infections.
Dacryocystitis
Trapped tears in the nasolacrimal sac can create the perfect breeding ground for bacteria. An infected nasolacrimal sac is called dacryocystitis. The symptoms include:
- Fever
- Redness, swelling and tenderness beside the bridge of the nose, next to the affected eye.
- In severe cases, the infected sac may form an abscess.
A range of causes
Some of the causes of a blocked tear duct include:
- Congenital conditions - some babies are born with a blockage within the tear duct system, usually the nasolacrimal duct. The thin membrane that seals the nasolacrimal duct in utero fails to open at birth.
- Chronic nose infections - chronic sinusitis may irritate the tissues and form scars, which block the tear duct system.
- Nose trauma - such as a broken nose. The injured tear duct system may be blocked by scar tissue.
- Nose polyps - a polyp is a protrusion growing out of a membranous lining. It looks like a ball on the end of a slim stalk. People with allergies such as hay fever are more prone to nasal polyps. These growths may obstruct the tear duct system.
- Conjunctivitis - infection and inflammation of the conjunctiva, which is the thin membrane covering the eye. In rare cases, the tear duct system may become infected and blocked, especially after some viral infections.
Diagnosis methods
A blocked tear duct is diagnosed using a number of tests, including:
- Physical examination - including medical history.
- Ophthalmic examination - to check for other possible causes.
- Particular tests to check for tear drainage - for example, a special fluid is flushed into the affected tear duct opening. A diagnosis of blocked tear duct is made if the patient can’t taste the fluid in their throat.
- X-ray or CT scan - taken of the tear duct area (dacryocystogram).
