Indication
Nasolacrimal duct obstruction (NLDO) typically presents as tearing and can be congenital or acquired. A variety of etiologies other than NLDO can produce excessive tearing, or epiphora, including punctal or canalicular obstruction, poor tear pump mechanism, eyelid malposition, ocular surface disorders, and hypersecretory disorders. However, NLDO represents the most common cause of persistent epiphora. The reported incidence of NLDO is 20 per 100,000.
Pediatric patients presenting with tearing should be evaluated by a pediatric ophthalmologist to rule out congenital glaucoma in addition to congenital NLDO. The most common cause of congenital NLDO is incomplete canalization of the duct at its distal aspect, leading to obstruction of flow at the level of the valve of Hasner. Spontaneous resolution may occur in the first few months of life, or it may remain obstructed, requiring further intervention, typically around 12 months of age. This chapter focuses on the evaluation and management of acquired forms of NLDO.
Acquired NLDO can be idiopathic (primary) or secondary to local or systemic disease processes. History of previous infections of the lacrimal sac, punctal plug placement, trauma or sinonasal surgeries, and systemic inflammatory, autoimmune, or neoplastic diseases should be elicited. Previous chemotherapeutic or radiotherapy treatment may also contribute to developing NLDO, specifically radioactive iodine (RAI). ,
The indications for in-office lacrimal probing and irrigation are persistent epiphora (chronic tearing), history of a previous episode of an enlarged, erythematous canaliculus or lacrimal sac (consistent with canaliculitis and/or dacryocystitis, respectively), and post-surgical evaluation of patency after a dacryocystorhinostomy.
During an active episode of infection (dacryocystitis or canaliculitis), irrigation of the lacrimal system is usually deferred to prevent creation of false passages within the friable, infected tissue.
Technique
Knowledge of the anatomy of the nasolacrimal system and its variations is key in the assessment of nasolacrimal duct obstruction. The lacrimal system is divided into an upper system and a lower system ( Fig. 23.1A ). The upper system includes the puncta and canalicular system; the lower lacrimal system includes the lacrimal sac and nasolacrimal duct. The puncta are 0.2- to 0.5-mm openings in the medial aspect of the upper and lower lids, approximately 5 to 6 mm lateral to the medial canthus. The first 2 mm of the canalicular pathway runs vertically, after which a 90-degree inflexion continues horizontally for about 8 to 10 mm toward the common canaliculus. Intricate anatomical relationships create a lacrimal pump and valve mechanism to promote drainage of tears through the puncta and into the canaliculi and lacrimal sac. Anatomic variations exist; approximately 2% to 10% of patients do not have a common canaliculus and the individual upper and lower canaliculi empty directly into the lacrimal sac. , The lacrimal sac is about 12 to 15 mm long and is surrounded by the orbicularis anteriorly and posteriorly, aiding in the movement of tears. The nasolacrimal duct then extends inferiorly about 12 mm in a posterior and lateral direction and exits under the inferior meatus ( Fig. 23.1B ).
Anatomy of the lacrimal system. (A) Coronal view of the nasolacrimal pathway, depicting the average length of each segment of the pathway from the punctal openings to canaliculi, common canaliculus, lacrimal sac, and nasolacrimal duct as it empties into the inferior meatus. (B) Sagittal view of the nasolacrimal duct as it relates to the nasal anatomy.
Obstruction can occur and be identified at any level within the pathway, from the puncta, canaliculi, common canaliculus, within the nasolacrimal duct, or distally as the nasolacrimal duct empties into the inferior meatus. Canalicular obstruction can exist in patients with a history of punctal plug placement, cytotoxic/antimetabolite systemic chemotherapy, cicatrizing autoimmune diseases, trauma to eyelids with canalicular laceration, or a history of viral cicatrizing conjunctivitis. Treatment of complete canalicular obstruction often requires a bypass with a glass Jones tube (conjunctivodacryocystorhinostomy [CJCDR]) and is beyond the scope of this chapter. Occasionally mild canalicular stenosis can be addressed with balloon dacryoplasty and stents; however, CJDCR is likely required.
External examination of the puncta and medial canthal structures can identify scarring or punctal stenosis. The medial canthus should be palpated to detect masses, distension of the lacrimal sac, or reflux from the punctum. An erythematous, edematous punctum accompanied by punctal discharge suggests canaliculitis, which should be managed with topical antibiotics and canaliculotomy with or without canalicular intubation. Any lesion above the medial canthal tendon raises suspicion for malignancy or an etiology other than lacrimal etiology. Tenderness over the lacrimal sac points to an inflammatory or infectious process, which may be accompanied by reflux of mucoid or mucopurulent discharge through either puncta. The authors perform bacterial culture and Gram stain of any purulent discharge and treat empirically with oral and topical antibiotics. Bloody or pink-stained discharge from the punctum occurring spontaneously or after irrigation should alert the clinician to consider a nasolacrimal neoplasm and recommend further investigation with computed tomography (CT) imaging with contrast.
The tear meniscus height can be measured with slit-lamp examination or direct visualization as a useful diagnostic indicator of NLDO. In patients without NLDO, the normal tear meniscus level is 0.2 mm, and in patients with obstruction, it is elevated at about 0.6 mm. The ratio of the tear meniscus level between the obstructed and unobstructed sides can also be calculated, with a ratio of 1.5 or higher suggesting NLDO.
The fluorescein dye disappearance test can also help assess lacrimal drainage; however, it is not specific for NLDO. One drop of fluorescein is placed in the inferior cul-de-sac, and after 5 minutes, the patient is reassessed using a cobalt blue–filtered light. The dye will create an iridescent yellow hue when viewed under such light. In normally functioning systems, only scant fluorescein remains along the lower eyelid margin in the tear meniscus after 5 minutes. NLDO is suspected if more dye is present or if fluorescein runs down the patient’s cheek.
Other tests of the lacrimal system include Jones I and Jones II testing, but these are less commonly used. The Jones I test is performed by instilling fluorescein in the inferior fornix, waiting 2 minutes, and placing a cotton tip under the inferior meatus. A positive (normal) Jones I collects fluorescein in the cotton tip. If no fluorescein is identified in the nose, then the Jones II test can be performed by irrigating the lacrimal system with a cannula and then placing a cotton tip into the inferior meatus. The reliability of the Jones I and II tests can be confounded by factors such as tear production and amount of fluorescein instilled, leading to a high rate of false-negative tests. Additionally, these tests still do not allow for clear differentiation of a patent duct versus a partially obstructed duct. The authors primarily use probing and irrigation as the main in-office diagnostic tool.
Lacrimal probing and irrigation (step by step) (Video 23.1):
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The lower lid is placed on stretch in a lateral direction and punctum visualized. If the punctum is stenotic, a punctal dilator is used to gently dilate the opening.
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The cannula is oriented vertically (perpendicular to the eyelid margin) and advanced 2 mm vertically through the punctum, then angled horizontally (parallel to the eyelid margin) and advanced within the canaliculus. In the normal system, a hard stop will be identified after the irrigation cannula abuts the bone along the medial aspect of the sac, typically after 8 to 10 mm of advancement. If the canaliculus is obstructed, a soft stop will be identified prior to 8 to 10 mm of advancement.
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The presence of canalicular stenosis (difficulty advancing the cannula) or passage through membranes within the canaliculus should be documented, as well as the distance from the punctum to the location of the stenosis or membrane.
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A hard stop typically means the lacrimal sac has been entered; a soft stop typically means there is tissue obstructing the lacrimal system prior to the nasolacrimal duct.
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After the cannula has been advanced, irrigation is then performed by injecting fluid through the syringe (approximately 0.5 mL).
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If there is reflux of fluid, the examiner should document the percentage of reflux, if it is from the same or opposite punctum, and whether it contains mucoid or blood-stained discharge.
In-office nasolacrimal duct probing can be performed under local anesthesia in patients with epiphora due to nasolacrimal duct obstruction. However, the authors typically avoid probing the duct with Bowman probes in the office as it causes pain and does not significantly improve diagnostic accuracy over irrigation alone.
Outcomes
The primary goals of in-office lacrimal probing and irrigation are to determine patency of the nasolacrimal outflow system and to identify the specific location and degree of any obstruction ( Fig. 23.2A ).
Lacrimal probing and irrigation outcomes. (A) Patent nasolacrimal duct; irrigation of fluid leads to flow into the inferior meatus without resistance, no regurgitation is noted. (B) Canalicular obstruction; fluid regurgitates through the same punctum. (C) Common Canalicular obstruction; fluid regurgitates through the opposite punctum. (D) Partial nasolacrimal duct obstruction; some flow to the inferior meatus is noted, but fluid regurgitates through the opposite and/or same punctum. (E) Complete nasolacrimal duct obstruction; no fluid passage to the inferior meatus is noted, and all the fluid regurgitates through the same or opposite punctum.
When advancing the cannula, resistance to passage of the cannula may indicate a canalicular obstruction. If the resistance prevents advancement of the cannula and irrigation of fluid leads to 100% reflux from the same punctum with no fluid entering the nose, then a complete canalicular obstruction is diagnosed ( Fig. 23.2B ). The distance from the punctal opening to the area of obstruction should be noted. A complete common canalicular obstruction produces a “soft stop” at the level of the common canaliculus, about 8 mm distal to the punctum, often accompanied by reflux through the opposite punctum and some reflux through the same punctum as well ( Fig. 23.2C ).
Obstruction of the nasolacrimal duct can be complete or partial. Partial nasolacrimal duct obstruction is diagnosed when some of the fluid refluxes through the opposite punctum and some flows into the nose ( Fig. 23.2D ). Complete nasolacrimal duct obstruction is diagnosed when the cannula reaches a hard stop and irrigation results in 100% reflux through the opposite punctum ( Fig. 23.2E ). The reflux may contain mucus, and the patient will not feel or taste any fluid in their nose or throat.
Incomplete canalicular stenosis may be identified with resistance to passage of the cannula and/or fluid but with flow to the nose, sometimes with additional digital pressure applied to the syringe. In some instances, such areas of stenosis can be cautiously bypassed, but forceful insertion of the cannula may create a false passage.
Table 23.1 summarizes the diagnosis and management options in the evaluation of nasolacrimal duct obstruction.
Table 23.1
Diagnosis and Management of Nasolacrimal Duct Obstruction
| Irrigation Outcome | Diagnosis | Management |
|---|---|---|
| 100% Reflux through opposite punctum | Complete NLDO | DCR with stent placement |
| Fluid passage into nose with some reflux through opposite punctum | Partial NLDO | Antibiotic/steroid topical drops and reevaluate patency in 4–6 weeks, consider lacrimal stenting and/or DCR depending on patient’s symptoms |
| 100% Reflux from same punctum | Complete canalicular obstruction | Conjunctivodacryocystorhinostomy (CJDCR) with Jones tube placement |
| Resistance to passage of the cannula through canaliculus, with flow into nose | Canalicular stenosis | DCR with balloon catheter dilation and stent placement |
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