The examination of the nasolacrimal system begins with evaluation of the puncta. Not uncommonly, a child may have punctal atresia or agenesis. This may present with a veil or membrane consistent of conjunctiva and canalicular epithelium that occludes the punctal orifice. This membrane may be present within the punctal orifice or may lie over the punctum as a veil and appear only as a small dimple in the lid margin.

Less commonly, a child may have an actual congenital absence of the punctum. This can be attributed to failure or incomplete outbudding of the nasolacrimal core (Fig. 4.2). This specific abnormality has demonstrated an autosomal dominant inheritance pattern [2]. Syndromes associated with absent puncta include ectodactyly-ectodermal dysplasia-clefting syndrome (EEC syndrome) and lacrimo-dento-digital syndrome (Lewis-Hollister syndrome) [3].

Abnormalities of the canalicular system include developmental aberrations such as canalicular atresia or absence of the canalicular system. Canalicular atresia can be classified as proximal, mid-canalicular, or distal. Absence of the canalicular system may be attributed to the anomalous development of the epithelial core [1].

Lacrimal anlage ducts or lacrimal fistulae may result from additional extensions of the embryonic epithelial cord or as outpouchings from the developing canaliculi. Accessory channels may exist and communicate with the skin ending in the canalicular system, the lacrimal sac, or even the lacrimal duct. The openings of these channels may be on the skin below the punctum, at the lid margin, or at the medial aspect of the lower eyelid crease (Fig. 4.3).

Dacryoliths or stones are more commonly associated with acquired nasolacrimal duct obstruction and are not seen in congenital cases. There have been no reports of dacryoliths causing congenital nasolacrimal duct obstruction.

Abnormal canalization can lead to direct communication between the skin and the lacrimal sac. Canalization begins at the fourth month of gestation and can be caused by a defect in the optic end of the naso-optic fissure [4]. An internal fistula between the lacrimal sac and nasal cavity may also occur, although this is not a cause of obstruction.

Entrapment of fluid in an obstructed nasolacrimal system may present as a dacryocystocele. Clinically, this is seen as a mass below the medial canthus representing distention of the lacrimal sac (Fig. 4.4). Other clinical signs include presence of a bluish discoloration. The entrapped fluid may represent mucus (mucocele) or amniotic fluid (amniotocele). Dacryocystoceles occur more commonly in neonate females due to narrower nasolacrimal ducts in females compared to males. Rarely, an encephalocele may cause distention in the region of the lacrimal system. This occurs when the neural tube fails to close completely during fetal development. More commonly, this will present above the medial canthal tendon and may have associated pulsations. Hemangiomas and dermoids may also present with distention in the medial canthal region. Malignant tumors of the lacrimal sac are uncommon in the pediatric population. Imaging studies such as ultrasonography or nasal endoscopy may aid in the diagnosis.

A serious complication of a dacryocystocele occurs when there is a large intranasal cyst component causing blockage of the nasal cavity (Fig. 4.5). Diagnosis of a dacryocystocele with intranasal cyst is made through physical examination, clinical history, nasal endoscopy, and imaging. It is important to note that these patients occasionally do show the typical external enlargement of the lacrimal sac, as most of the distention is in the nasal cavity. These patients may repeatedly fail probing as the probe may not pass beyond the cyst wall. In these cases, imaging and/or nasal endoscopy is necessary and successful treatment has been reported with marsupialization of the cyst [5]. Neonates are obligate nasal breathers. Nasal obstruction caused by the presence of an intranasal cyst is a potential for acute respiratory distress and is especially evident during feeding and sleeping. When the child cries, the airway becomes more patent and the caregivers can note a “cyclic cyanosis.” If intranasal cysts obstruct both nasal airways, the neonate has a potentially life-threatening disorder. Also a child born with airway compromise can also have choanal atreasia, however the diagnosis of intranasal cyst should always be considered [6–8].