Saad Bidiwala

Introduction

Tearing is a frequent complaint in paediatric ophthalmology, with congenital nasolacrimal duct obstruction (CNLDO) being a leading cause. The condition arises from incomplete developmental opening of the nasolacrimal duct, typically at its distal end, near the valve of Hasner. While most cases resolve spontaneously within the first year of life, persistent obstruction can necessitate medical or surgical intervention. Recognizing the signs of CNLDO and implementing timely management is critical to avoid complications such as secondary infection or structural abnormalities affecting vision.

Pathophysiology

The nasolacrimal drainage system develops from epithelial cords that canalize progressively during gestation. In CNLDO, failure of canalization typically occurs at the distal duct, resulting in obstruction. This incomplete drainage leads to retention of tears and mucous, creating an environment conducive to bacterial colonization. Staphylococcus species and Streptococcus pneumoniae are common pathogens isolated in secondary infections.

Factors contributing to CNLDO include:

• Developmental anomalies: Persistence of a membranous obstruction at the valve of Hasner.
• Anatomic predisposition: Narrowing or tortuosity of the nasolacrimal duct.
• Familial or genetic syndromes: Associations with craniofacial abnormalities, such as in Down syndrome.

Clinical Presentation

CNLDO typically presents within the first few weeks of life with the following hallmark features:

• Epiphora (tearing): Persistent overflow of tears despite normal tear production.
• Mucopurulent discharge: Accumulation of mucus and debris in the conjunctival sac, exacerbated during crying.
• Crusting of eyelids: Especially noticeable upon waking.
• Absence of conjunctival injection: A distinguishing feature from infectious conjunctivitis.

In some cases, CNLDO can present as dacryocystocele, a bluish swelling over the medial canthus due to proximal blockage and distal cyst formation. This warrants urgent attention due to the risk of infection or respiratory compromise in neonates.

Diagnosis

CNLDO is primarily a clinical diagnosis based on history and physical examination. Key diagnostic steps include:

• Observation: Persistent tearing and discharge are often sufficient to suggest the diagnosis.
• Pressure test: Gentle compression over the lacrimal sac may elicit reflux of mucus or purulent material.
• Fluorescein dye disappearance test (FDDT): Instillation of fluorescein into the conjunctival sac followed by observation for drainage through the nasal passages. Retention of dye indicates obstruction.
• Imaging: Rarely required, but ultrasonography or dacryocystography may be used in atypical or refractory cases.

Management

Conservative Approach

Most cases resolve spontaneously by 12 months of age, necessitating a conservative approach as the initial step:

• Lacrimal sac massage (Crigler technique): Parents are instructed to apply firm pressure over the lacrimal sac in an upward and downward direction several times daily. This manoeuvre can help break through the membranous obstruction.
• Topical antibiotics: Prescribed only if secondary infection is suspected. Erythromycin ointment is commonly used.

Surgical Interventions

For persistent cases beyond 12 months or in instances of recurrent dacryocystitis, surgical intervention is indicated:

Probing and Irrigation

• Indications: First-line intervention for persistent obstruction after 1 year of age.
• Procedure: Performed under brief general anaesthesia. A thin probe is inserted into the punctum, passed through the nasolacrimal duct, and advanced to open the obstruction at the valve of Hasner. Success rates exceed 90% in uncomplicated cases.

Balloon Dacryoplasty

• Reserved for recurrent obstruction or complex cases. A catheter with an inflatable balloon is used to dilate the nasolacrimal duct.

Silicone Intubation

• A bi-canalicular silicone stent is placed to maintain patency in cases of severe stenosis or recurrent obstruction.

Dacryocystorhinostomy (DCR)

• A rarely needed procedure involving the creation of a new drainage pathway between the lacrimal sac and nasal cavity. Typically performed in older children or in association with craniofacial abnormalities.

Complications

Failure to manage CNLDO can result in:

• Dacryocystitis: Acute infection of the lacrimal sac, presenting with erythema, swelling, and tenderness over the medial canthus.
• Orbital cellulitis: Extension of infection into the orbital structures, requiring urgent systemic antibiotics.
• Amblyopia: Chronic obstruction and associated visual deprivation can impair normal visual development.

Prognosis

The prognosis for CNLDO is excellent, with most cases resolving spontaneously or responding to simple interventions. Surgical techniques, when needed, are highly effective with minimal complications. Early recognition and treatment are crucial to prevent long-term sequelae.

Conclusion

Congenital nasolacrimal duct obstruction is a common and manageable condition in paediatric ophthalmology. By understanding its clinical presentation, natural history, and available treatment options, clinicians can provide effective and timely care, ensuring optimal visual outcomes for affected infants. Collaboration with parents through education on conservative management plays a pivotal role in the early stages, while surgical interventions remain a reliable solution for persistent or complicated cases.