If the condition affects both the upper and lower canaliculi, punctal agenesis and atresia present as permanent tearing from shortly after birth. Complete punctal agenesis, with a total absence of any punctal structure (e.g., the annulus), is rare. It more commonly involves the lower punctum, probably arises from the nasolacrimal epithelial cord failing to reach the eyelid margin, and may be linked to other abnormalities of lacrimal cord formation (e.g., congenital fistulae) or to eyelid abnormalities (e.g., distichiasis).³ Punctal agenesis is also linked to ectodermal dysplasias⁴ (Fig. 9.2), Hay-Wells syndrome,⁵ and Levy-Hollister syndrome.⁶

Punctal atresia (“imperforate punctum”; “punctal membrane”) is more common than agenesis, may be partial, and is characterized by an epithelial membrane overlying the normal annular tissues present in the canalicular papilla (which is slightly raised above the eyelid margin).⁷

As canalicular agenesis arises from an incomplete or erroneous migration of the lacrimal epithelial cord toward the eyelid margin (Fig. 9.1), it is usually a more extreme form of punctal agenesis and almost always affects the area in continuity with the punctum. Only extremely rarely will exploration of a normal punctum reveal distal canalicular agenesis – by far the most common cause of this scenario being canalicular scarring due to previous probings.⁸

Lacrimal punctal duplication and supernumerary canaliculi in the eyelid are rare⁹ but may be associated with trisomy 21,¹⁰ the presence of preauricular sinuses, Waardenburg syndrome,¹¹ and Pashayan blepharonasofacial syndrome.¹² Anomalous development at the medial canthal conjunctivocutaneous junction can lead to an accessory, or “duplex,” punctum – often with an associated short length of canaliculus that either is blind ending or merges with a normal canaliculus (Fig. 9.3). Where a normal canaliculus is present, duplex puncta are often asymptomatic but can also be associated with lacrimal canalicular fistulae or diverticula of the lacrimal sac.

Lacrimal fistulae arise from abnormal invagination of the lacrimal epithelial cord into the medial tissues of the lower eyelid; extremely rarely, they may pass to the caruncle (“bifid caruncle”) (Fig. 9.4) or to the upper eyelid. They are characterized by an epithelial lining – either squamous epithelium where the skin dominates the track or, more commonly, cuboidal epithelium where the canalicular tissues dominate; in some cases, both epithelia are present.

Usually, unilateral, congenital fistulae may present as fluid leaking from a “pinhole” cutaneous dimple below the medial canthal tendon (Fig. 9.5) and almost always connect to the common canaliculus. In contrast, fistulae to the lacrimal sac are not congenital, arising from drainage of an acute dacryocystic abscess (Fig. 9.6), and unless very longstanding, are not epithelial lined. Congenital lacrimal fistulae are associated with trisomy 21, ectrodactyly–ectodermal dysplasia–cleft lip/palate (EEC) syndrome, and some syndromes with hypertelorism or hypospadias.

Arising from the common canaliculus, a congenital fistula may be permanently dry if the nasolacrimal duct has sufficient capacity to drain tears, intermittently discharging watery tears if a patent nasolacrimal duct has insufficient capacity to deal with reflex tearing, or continuously watering where there is no nasolacrimal drainage. Extremely rarely, these anomalies will present late in life when acquired nasolacrimal duct obstruction has occurred or as an inflammatory “fistulitis” as a result of retained oil and squamous debris in fistulae where cutaneous epithelium predominates.

Management

Clearly, a nondraining fistula only requires excision if fistulitis occurs. A fistula that weeps intermittently – for example, with a nasal cold – probably needs no intervention unless there is skin excoriation, and it is here that controversy exists.

Controversy: Some advocate excision of the fistula alone, but this carries a risk of the track reopening or the child developing a persistently “watering eye” (although more accurately described as watering “around the eye”) – both occurring as a result of reducing drainage capacity (by removing the fistula) without increasing the alternative route for flow. Others advocate placement of a silicone stent or a DCR to increase drainage capacity and reduce this risk (Fig. 9.7).¹³ A compromise is to check the lacrimal outflow patency at time of fistula excision and only perform stenting or DCR when distal blockage is identified or clinically where fistular drainage is continuous.¹⁴