A blockage in the nasolacrimal duct hinders the flow of tears from the eye into the nasal cavity, causing nasolacrimal duct obstruction (NLDO). This can lead to tear overflow, recurring eye infections, and other issues.
Epiphora
The involuntary overflow of tears down one’s cheek is known as epiphora. This condition can range from occasional discomfort to persistent overflow. It occurs due to an imbalance between tear production and drainage. Factors affecting the lacrimal drainage system include the anatomy of the system, the eyelids’ position, and tear drainage physiology.
Diagnosis of Epiphora Causes
To diagnose the cause of epiphora, it’s essential to determine if it’s due to decreased tear drainage or increased lacrimation. Potential causes of increased tear production include:
- Trichiasis (abnormal eyelash growth)
- Superficial foreign bodies
- Eyelid malpositions
- Disorders of the eyelid margins
- Tear insufficiency or instability
- Irritation of cranial nerve V
If these conditions are not present, an anomaly in tear drainage is considered.
Classification of Tear Outflow Abnormalities
Tear outflow abnormalities can be classified into two categories:
- Functional Diseases: These include poor lacrimal pump function due to a misplaced punctum, slack eyelids, weak orbicularis muscle, or palsy of cranial nerve VII.
- Anatomical Diseases: These involve physical blockages anywhere in the upper or lower lacrimal drainage systems.
Physiology and Anatomy
The nasolacrimal system consists of several components:
- Lacrimal Gland: Secretes tears.
- Lacrimal Puncta: Openings in the upper and lower eyelids where tears enter the drainage system.
- Canaliculi: Small channels that transport tears from the puncta to the lacrimal sac.
- Lacrimal Sac: Collects tears before they pass into the nasolacrimal duct.
- Nasolacrimal Duct: Extends from the lacrimal sac to the nasal cavity, where tears are drained.
Causes of Nasolacrimal Duct Obstruction (NLDO)
Congenital Causes
- Incomplete Canalization:
- Membranous Obstruction: Membrane at the duct’s distal end fails to open.
- Bony Obstruction: Bone causes blockage within the duct.
- Developmental Anomalies:
- Craniofacial Abnormalities: Disorders affecting bone development, such as Down syndrome.
- Genetic Predispositions: Genetic factors.
Acquired Causes
- Inflammatory: Chronic sinusitis, granulomatous inflammation (e.g., sarcoidosis, Wegener’s granulomatosis).
- Infectious: Dacryocystitis, chronic conjunctivitis causing scarring.
- Traumatic: Trauma to the nose or face, surgical trauma.
- Neoplastic: Benign (e.g., dacryocystic mucoceles, papillomas) and malignant tumors (e.g., lymphoma, squamous cell carcinoma).
- Age-Related: Degenerative changes and hormonal alterations.
- Systemic Diseases: Sarcoidosis, lymphoma.
- Iatrogenic: Medication side effects, damage from radiation therapy.
Symptoms
- Epiphora: Excessive tearing.
- Recurrent eye infections: Due to stagnated tears.
- Mucopurulent Discharge: Indicative of infection.
- Swelling and tenderness: Around the inner corner of the eye.
Diagnosis
- Clinical Examination: Palpation and inspection to evaluate tear drainage.
- Fluorescein Dye Disappearance Test: Assesses tear drainage efficiency.
- Irrigation and Probing: Checks for obstructions.
- Imaging Studies: MRI, CT scan, or dacryocystography to visualize the nasolacrimal duct.
Treatment
Conservative Management
- Massage: The Crigler massage technique applies gentle pressure to open the nasolacrimal duct, especially effective in infants.
- Antibiotics: To treat or prevent infections related to NLDO.
Surgical Procedures
- Probing: Inserting a probe to clear the obstruction, typically done in infants under anesthesia.
- Balloon Catheter Dilation: A small balloon is inserted into the duct and inflated to clear the blockage.
- Intubation: Silicone tubes are placed in the nasolacrimal duct to keep it open, usually removed after a few months.
- Dacryocystorhinostomy (DCR): Creating a new tear drainage channel directly into the nasal cavity, which can be done endoscopically or externally.
- Laser Dacryocystorhinostomy: A laser is used to create a new opening in the duct, which is less invasive and has a shorter recovery time.
Postoperative Care
- Antibiotic Eye Drops: To prevent infections.
- Steroid Drops: To reduce inflammation.
- Follow-up Visits: To ensure the duct remains open and monitor for any complications.
Prognosis
- Infants: High success rates with conservative treatments and probing.
- Adults: Generally good outcomes with surgical procedures such as DCR.
Complications
- Chronic Dacryocystitis: Persistent infection of the lacrimal sac.
- Abscess Formation: Possible with severe infections.
- Orbital Cellulitis: A serious infection that can spread to surrounding tissues.
Conclusion
Nasolacrimal duct obstruction (NLDO) causes excessive tearing, recurrent infections, and discomfort by blocking the flow of tears from the eye to the nasal cavity. The condition can result from congenital factors like incomplete canalization or developmental anomalies, as well as acquired causes including inflammation, infections, trauma, tumors, age-related changes, systemic diseases, and iatrogenic factors. Symptoms include epiphora, recurrent infections, mucopurulent discharge, and swelling or tenderness. Diagnosis involves clinical examination, tear drainage tests, and imaging studies. Treatment ranges from conservative measures like massage and antibiotics to surgical procedures like probing, balloon catheter dilation, intubation, and dacryocystorhinostomy. Postoperative care includes antibiotics, steroid drops, and follow-up visits. The prognosis is generally good, with successful outcomes in both infants and adults. Potential complications include chronic dacryocystitis, abscess formation, and orbital cellulitis.
