What You Should Know About a Tear Duct Blockage
What is a Tear Duct Blockage or Obstruction?
A tear duct blockage (otherwise known as a nasolacrimal duct obstruction) is a common condition that causes excessive tearing and watering in one eye.
The tearing typically runs down the cheek because the lacrimal drainage system is blocked within the nasolacrimal duct.
Anatomy of the Tear Drainage System
The eyes naturally produce tears to keep the surface of the eye moist and allow for smooth movement of the eyelids.
These tears drain through a system called the nasolacrimal drainage system. This begins with a small opening on the edge of the eyelids called the punctum.
Once tears pass into the punctum, they travel through a small tube called the canaliculus into the lacrimal sac.
The lacrimal sac is located above the nose and drains into the opening of the nose through the nasolacrimal duct which is controlled by the valve of Hasner.
After tears are drained from the lacrimal sac into the nose, the tears are either absorbed into the tissue of the nose or excreted through the nose.
Causes of Nasolacrimal Duct Obstruction
The most common causes of nasolacrimal duct obstruction depend on the age of the person with the condition.
In children, the most common cause is a congenital issue with the valve of Hasner inside the nasolacrimal duct.
In adults, the most common cause is due to age related narrowing of the nasolacrimal duct and the second most common is due to inflammation of the sinus surrounding the nasolacrimal duct.
Congenital Issues with Valve of Hasner
The most common cause of nasolacrimal duct obstruction in children, a congenital issue with the valve of Hasner is typically present at birth and affects infants and toddlers.
In these cases, the valve of Hasner does not allow for proper drainage from the lacrimal sac through the nasolacrimal duct into the nose.
Many of these cases will resolve as the child grows and will not require any treatment. If treatment is needed, options include massaging the nasal region, irrigating the drainage system, or surgery.
Age Related Narrowing of the Nasolacrimal Duct
With age, the nasolacrimal duct can narrow through a process called involutional stenosis. This narrowing can restrict the flow of the tears from the lacrimal sac into the nose.
Unlike cases in children, the age-related changes will not usually resolve without intervention. The treatments may include dilating and irrigating the drainage system, or a surgery known as dacryocystorhinostomy (DCR).
Inflammation of Surrounding Sinuses
The nasolacrimal duct is located within an air-filled cavity in the face known as the maxillary sinus.
If there is inflammation in the maxillary sinus the sinus can compress the nasolacrimal duct and inhibit the tear drainage into the nose.
The inflammation can be caused by an infection, such as bacteria, a medical condition, such as rheumatoid arthritis, or allergies.
In cases where the maxillary sinus is inflamed and causing the nasolacrimal duct to be obstructed, treating the cause of the inflammation, and utilizing medication to reduce inflammation can relieve the obstruction.
Complications of Nasolacrimal Duct Obstruction
If the nasolacrimal duct obstruction is not treated it can produce a fluid-filled mass called a dacryocele or result in infection within the lacrimal sac.
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