Congenital Nasolacrimal Duct Obstruction (CNLDO)

The nasolacrimal duct doesn't canulate until birth, and there may be a persistent membranous obstruction at the bottom end of the nasolacrimal duct in up to 70% of neonates (dacryostenosis).¹ Spontaneous resolution occurs in most cases 6-20% of babies will still have symptoms at age one month; with less than 1% still having symptoms at one year of age.^2,3

Rarely there may be other abnormalities - agenesis or abnormalities of the puncta, lacrimal sac, duct or absence of valves (valve of Hasner ±valve of Rosenmüller).

Epiphora (watering eyes), sticky eyes, recurrent conjunctivitis, crusting of eye lids, ±boggy swelling over inner canthal region from which it may be possible to express pus.

Diagnosis is usually straightforward - but always consider:

• Congenital dacryocystocele (uncommon tense blueish swelling of the lacrimal sac) - acute inflammation occurs commonly and there may be an associated intranasal cyst - refer to ophthalmology.
• Congenital conjunctivitis (ophthalmia neonatorum) or other conjunctivitis.
• Corneal abrasions
• Congenital Glaucoma
• Other congenital abnormality - eg Albinism or aniridia.

Fluorescein dye disappearance test may be helpful - a small drop of dye is instilled into both eyes - which will normally disappear over 5 minutes if duct is patent, (and may subsequently be visible in the nostril using blue light).⁴

Conservative management is appropriate in most cases because of high rate of spontaneous resolution. There is some evidence that teaching parents to massage the tears down the nasolacrimal duct may speed resolution.³ Probing will clear 95% of those cases where resolution doesn't occur - and may be appropriate before age one year if patient is very symptomatic. Antibiotic eye drops should only be used if there is infection i.e conjunctival redness rather than just discharge.

Probing is usually performed with a light general anaesthetic in the UK, although may be performed without GA by those with suitable training and experience (often done in the consulting room in the USA). Nasendoscopy allows direct visualisation of the lower end of the nasolacrimal duct which increases the accuracy of the procedure.

"Early probing" during the first year of life of course means symptoms resolve immediately in almost all cases (optimum time seems between 4-6 months)^3,5 - but the long term consequences of adopting this "unnecessary" procedure are currently unknown.

If still unsuccessful after 2-3 probing attempts, then a dacryocystorhinostomy (DCR) is performed.

Rare patients with congenital punctal agenesis (of both puncti) almost always have canalicular agenesis as well and require conjunctival dacryocystorhinostomy (usually delayed until aged >10 years).