Congenital Nasolacrimal Duct Obstruction

The nasolacrimal duct usually canalises at 8 months of fetal life¹ but there is commonly a delay in this developmental process which can result in residual membrane tissue or stenosis at any level in the nasolacrimal system - from the canaliculi to the extreme end of the nasolacrimal duct underneath the inferior turbinate.² Persistent membranous obstruction at the bottom end of the nasolacrimal duct occurs in up to 70% of neonates (dacryostenosis).³ However, only 2-4% of newborns exhibit the clinical phenomena of nasolacrimal duct obstruction.

Rarely, there may be other associated abnormalities - agenesis or abnormalities of the puncta, lacrimal sac, duct or absence of valves (valve of Hasner ± valve of Rosenmüller). Very pronounced/severe obstruction is associated with systemic abnormalities in 25% of cases.²

Epiphora (watering eyes) which develops within 6 weeks of birth,⁴ sticky eyes, recurrent conjunctivitis, crusting of the eyelids, ± boggy swelling over the inner canthal region from which it may be possible to express pus. These infants may less commonly present for the first time with dacryocystitis. It is bilateral in a third of cases.⁴

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 - this is another important paediatric childhood condition that may present with epiphora. Photophobia, a difference in eye size (compare the diameter of the cornea of each eye with a simple desk-top clear ruler) and clouding of the cornea suggest this to be much more worrying pathology which needs urgent ophthalmic assessment.²
• Other congenital abnormality - e.g. albinism or aniridia.

Fluorescein dye disappearance test may be helpful - a small drop of dye is instilled into both eyes and will normally disappear over 5 minutes if the duct is patent, and may subsequently be visible in the nostril using blue light.²

Conservative

In most cases, simple massaging of the ducts may be enough because of the high rate of spontaneous resolution. Parents should massage the sac six times a day by firm pressure on the medial upper lid. There is some evidence that this may speed resolution.⁵ Use topical antibiotics for any episodes of associated conjunctivitis (i.e. red conjunctiva as opposed to simple discharge).⁴

Surgical

The timing of surgical intervention is tricky. The fact that spontaneous resolution is likely has to be balanced with the fact that surgical success decreases with age.⁶ Current practice is to defer surgery until 12 months of age. At that point, probing of the ducts under a very light anaesthesia may be done. Nasoendoscopy allows direct visualisation of the lower end of the nasolacrimal duct, which increases the accuracy of the procedure. This will clear 95% of those cases where resolution doesn't occur spontaneously. ²

Probing may occasionally be considered before age one year if the patient is very symptomatic. 'Early probing' results in symptoms resolving immediately in almost all cases (optimum time seems between 4-6 months)^5,7 - but the long-term consequences of adopting this 'unnecessary' procedure are currently unknown and the child is faced with the usual risks associated with simply having a general anaesthetic. If still unsuccessful after 2-3 probing attempts, then a dacryocystorhinostomy (DCR) is performed. Balloon catheter dilation is another, less invasive approach.⁸

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

Conjunctivitis is the most common complication. This can be managed with simple topical antibiotics. The baby may also be born with - or develop - a dacryocystoceole (mucocele) whereby fluid (e.g. amniotic fluid) enters the sac and is retained by the non-patent duct. ⁴This may lead to acute dacryocystitis. The risks of probing include:¹

• Failure - the risks of this increase exponentially with age and number of probings
• Creation of a false passage
• Bleeding (serious: 1-2% of cases)²
• Bronchospasm

Spontaneous resolution occurs in most babies, with 90-96% of cases resolving at a year and a further 60% of the remaining children spontaneously regaining patency at 2 years of age.

1. Jackson TL. Moorfields Manual of Ophthalmology, Mosby (2008).
2. Bashour M; Nasolacrimal Duct, Congenital Anomalies, eMedicine (June 2009).
3. Cassady JV; Developmental anatomy of nasolacrimal duct; AMA Arch Ophthalmol. 1952 Feb;47(2):141-58.
4. Willshaw H, Scotcher S, Beatty S. A Handbook of Paediatric Ophthalmology, HE Willshaw (2000).
5. Young JD, MacEwen CJ; Managing congenital lacrimal obstruction in general practice. BMJ. 1997 Aug 2;315(7103):293-6.
6. Takahashi Y, Kakizaki H, Chan WO, et al; Management of congenital nasolacrimal duct obstruction. Acta Ophthalmol. 2009 Jul 21. [abstract]
7. Paul TO, Shepherd R; Congenital nasolacrimal duct obstruction: natural history and the timing of optimal intervention; J Pediatr Ophthalmol Strabismus. 1994 Nov-Dec;31(6):362-7. [abstract]
8. Repka MX, Melia BM, Beck RW, et al; Primary treatment of nasolacrimal duct obstruction with balloon catheter dilation J AAPOS. 2008 Oct;12(5):451-5. [abstract]

• Nasolacrimal duct obstruction (nasolacrimal drainage dysfunction), Clinical management guidelines, The College of Optometrists, January 2009.
• Repka MX, Chandler DL, Beck RW, et al; Primary treatment of nasolacrimal duct obstruction with probing in children Ophthalmology. 2008 Mar;115(3):577-584.e3. Epub 2007 Nov 8. [abstract]