Tears are produced by the main and accessory lacrimal glands situated under the outer part of the upper eyelid. Tears are drained out of the eyeball through the inner aspect of the eyelids – through small holes called punctae. This forms the initial “top” end of the nasolacrimal duct. The duct continues to drain into the back of the nose. (see diagrams). CNLDO occurs when a membrane obstructs the bottom end of the duct, inducing blockage of the tear duct and hence a watery eye.

Infants with CNLDO present with a persistent watery eye (or eyes), sometimes with mucous discharge (yellowish-green). Most infants become symptomatic during the first month of life. The periocular skin (skin surrounding the eyeball) can become chapped or dry due to continual exposure to tears and excessive wiping of these tears. Recurrent conjunctivitis can occur due to the stagnant collection of tears on the eye increasing the risk of bacterial contamination and conjunctivitis.

CNLDO can either be treated with conservative management or with a surgical procedure.

All cases are initially treated with conservative management, due to the large proportion of infants that experience spontaneous resolution and opening of the tear duct.

Conservative management involves massaging of the ducts, specifically the canaliculus which is situated on the outer upper part of the nose. Gentle pressure is applied to this area with downward strokes, in an effort to raise pressure and encourage opening of the duct. Any discharge from the eyes should be regularly cleaned. In the case of conjunctivitis, topical antibiotics are used.

Surgical intervention is recommended for infants over the age of 12 months with persistent symptoms. This will be required to be performed at a surgical operating facility and under a General Anaesthetic. A fine flexible probe is inserted into the tear duct to physically open the duct pushing through the membrane. This procedure has a 90% success rate.

In the event of persistent symptoms following this initial procedure, further surgery may be required and can involve stent insertion or balloon dacryoplasty.

Complications following nasolacrimal duct probing and stent insertion include nasal bleeding, restenosis of the duct and creation of a false passage of the duct, all of which are rare.

The prognosis for CNLDO resolution by one or more surgical procedures is excellent with a high success rate. Once the duct is patent, it is very rare to become stenosed or blocked again later in life.