Hospital for Sick Children's, The: Atlas of Pediatric Ophthalmology & Strabismus, 1st Edition

3

Lacrimal

Alex V. Levin

Thomas W. Wilson

Dan Deangelis

Robert Pashby

Jeffery Hurwitz

The lacrimal system includes the lacrimal gland, upper and lower lid puncta, upper and lower lid canaliculus, lacrimal sac, and nasolacrimal duct. The lacrimal gland is responsible for the production of the middle (aqueous) layer of the tear film. It is innervated by the lacrimal branch of the middle division trigeminal nerve. The superficial layer of the tear film is contributed by the meibomian glands of the lids (seeChapter 2: Lids and Adnexa). The inner layer of the tear film is made by the conjunctival goblet cells (see Chapter 4: Conjunctiva). As the tear film is produced continuously, it must have a place to drain. The nasolacrimal system collects the tears via the puncta, which must be patent and lie in apposition to the surface of the globe so that they may collect the tear film drainage. If there is inadequate drainage, epiphora will occur. Flow of tears into the nasolacrimal system is facilitated by the orbicularis muscle and other muscles surrounding the sac creating a pumping mechanism. If the lids are hypotonic, malpositioned, or floppy (see Chapter 2: Lids and Adnexa), epiphora may result as the tears are unable to gain access to the puncta.

Each punctum lies at the peak of an elevated papilla. There is a vertical path of approximately 2 mm followed by a 90-degree turn into the canaliculus. The upper and lower canaliculi join at the medial canthus to form the common canaliculus, which then enters the lacrimal sac. The lacrimal sac is located in a bony sulcus in the anterior medial orbital wall such that only its upper third is exposed. The remainder of the sac and the nasolacrimal duct lie within the bone of the anterior orbit and face. The nasolacrimal duct opens into the nose as the inferior meatus under the ipsilateral inferior turbinate. Disease within the nose may also cause obstruction.

Although nasolacrimal system abnormalities are commonly isolated, they may also be seen in a wide variety of syndromes, particularly those that affect midline disorders or the lids. Dysfunction can also occur secondary to trauma, tumor, and infection. Likewise, the lacrimal gland can be affected by infection, tumor, or external influences such as radiation. Lacrimal gland dysfunction may also occur in Sjögren and other autoimmune diseases (see Chapter 27: Rheumatology). Dysfunction of the lacrimal gland results in dry eye.

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Figure 3.1 Punctal Atresia

Punctal atresia is complete absence of the lacrimal punctum. There is usually no papilla, although a small indentation in the area where the punctum should be may occur. Patients usually have symptoms of epiphora without significant discharge. Treatment is usually not necessary for absence of the upper punctum as shown here. Lower lid punctal atresia is more likely to be symptomatic. Treatment options include surgical cannulation and placement of silicone tubes for several months. If no canaliculus can be found, then a conjunctival-lacrimal sac tube (Jones tube) may be necessary.

 

Figure 3.2 Punctal Membrane

A punctal membrane is a grayish membrane over the normal punctum. There is typically a papilla, although the puncta may not be easy to recognize or may be stenotic. Symptoms will likely include epiphora and scant discharge, especially if the lower puncta is involved. Surgical penetration of the membrane and probing will often relieve the symptoms of epiphora. As the puncta are derived from surface ectoderm, unlike the mesoderm-derived nasolacrimal duct, the distal system is usually intact.

 

Figure 3.3 Lacrimal Sac Fistula

Lacrimal sac fistula is a direct connection between the nasolacrimal sac and the skin in the area of the medial canthus. The fistula appears as a small hole in the skin below the medial canthus (arrow) through which tears may emanate. Treatment options include simple probing to relieve any resistance to normal tear flow or elimination of the fistula with cautery. This patient required a nasolacrimal duct tube, which can be seen crossing from the lower to upper puncta and was tied within the nose.

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Figure 3.4 Nasolacrimal Duct Obstruction

Nasolacrimal duct obstruction presents with epiphora and mucous discharge starting at or shortly after birth. The obstruction is in the distal nasolacrimal duct. There is an absence of conjunctival injection, cornea cloudiness, or buphthalmos, thus ruling out glaucoma or infection. The poor drainage will allow for the mucoid components of the tear film (inner and outer layers) to precipitate out and appear as a discharge, which is usually worse on waking from sleep. This child has copious discharge with a strand extending between the lids. Tearing, wet lower lid lashes, and chronic skin changes in the lower lid subciliary area are common. Treatment includes nasolacrimal sac massage in the area of the lacrimal fossa, and nasolacrimal duct probing.

 

Figure 3.5 Lacrimal Sac Mucocele

Lacrimal sac mucocele, also known as dacryocystocele or amniotocele, results from a completely imperforate inferior meatus resulting in an inability of the nasolacrimal duct to drain tears and necrotic debris from the coring out of the mesoderm during embryonic formation of the duct. A “ball valve” effect is created proximally, resulting in the outpouching of the lacrimal sac, which presents as a small bluish mass (arrow) below the medial canthal tendon. The medial canthus may be deflected upward, as seen in the right image of a child with a left infected mucocele. Treatment is recommended before infection occurs.

 

Figure 3.6 Lacrimal Mucocele

The membrane covering the entrance of the nasolacrimal duct into the nose is often distended, creating a cystlike structure underneath the inferior turbinate, as seen in the left image endoscopically and in the right image by computed tomography scan (arrow). As infants often present during the first 2 weeks of life, respiratory problems may be noted, especially in breast-fed babies when on the ipsilateral breast (i.e., baby with right mucocele feeding on the mother's right breast) as the nipple compresses the nares on the unaffected side. We recommend nasal endoscopy in all cases of lacrimal sac mucocele to ensure that the nasal cyst is extirpated.

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Figure 3.7 Dacryocystitis

Dacryocystitis is an infectious enlargement of the nasolacrimal sac. In infancy, over 95% of patients will have an underlying lacrimal sac mucocele. Beyond the first few weeks of life, mucocele is unlikely, but history may reveal pre-existing nasolacrimal duct obstruction. We recommend treatment with intravenous antibiotics. After the infection has been reduced, we recommend probing and, in the first month of life, nasal endoscopy to search for and remove a cyst under the inferior turbinate (see Fig. 3.6). The infected sac should not be incised percutaneously.

 

Figure 3.8 Dacryoadenitis

Dacryoadenitis is the term for infection or inflammation of the lacrimal gland, as seen in this child's right eyelid. The enlarged lacrimal gland will present as a swelling of the lateral upper lid and may, as demonstrated here, extend from the upper fornix onto the surface of the globe. Common infectious causes in children include mononucleosis, rubeola, or herpes zoster. Noninfectious causes include pseudotumor and lymphoma.