American Ophthalmological Society thesis). Trans Am Ophthalmol Soc. 2012;110:74–93.
Nasolacrimal Duct Obstruction
Nasolacrimal duct obstruction is by far the most common lacrimal system disorder encountered in pediatric ophthalmology, occurring in approximately 5% of full-term newborns. Usually, a thin mucosal membrane at the lower end of the NLD, at the valve of Hasner, is the cause (see Fig 19-7A).
Clinical Features
Infants who have typical NLDO usually present within the first month of life with epiphora, recurrent periocular crusting, or both (Fig 19-4). Symptoms are usually chronic and intermittent, and bilateral involvement is common. Digital pressure over the lacrimal sac usually results in retrograde discharge of mucoid or mucopurulent material. Culture of the discharge typically reveals the presence of multiple strains of bacteria, but this information is ordinarily not necessary for clinical management.
Figure 19-4 Bilateral nasolacrimal duct obstruction. Note epiphora and periocular crusting without evidence of inflammation.
(Reproduced with permission from Lueder GT. Pediatric Practice Ophthalmology. New York: McGraw-Hill Professional; 2011:55.)
The differential diagnosis of NLDO includes infantile glaucoma, conjunctivitis, epiblepharon with corneal irritation due to misdirected eyelashes, and various corneal disorders. The presence of epiphora is the primary reason that these entities may be mistaken for NLDO, but the associated findings (eg, enlarged corneas and Haab striae in glaucoma, conjunctival injection in conjunctivitis, visible eyelid abnormalities in epiblepharon, and corneal surface abnormalities in corneal disorders) make the diagnosis of NLDO relatively easy to establish.
An important clinical characteristic of NLDO is that infants with this disorder typically do not appear bothered by it. In addition, the cornea and conjunctiva are usually otherwise normal. The presence of photophobia, visible conjunctival changes, or corneal surface abnormalities should prompt the examiner to look for diseases other than NLDO.
Some studies have shown an association between NLDO and anisometropia, which may cause
amblyopia. Because of this, and because of the need to rule out the disorders noted previously, children with NLDO who present to an ophthalmologist should undergo a full ophthalmic examination, including refraction.
Nonsurgical Management
There is a high rate of spontaneous resolution of NLDO, with approximately 90% of patients improving within the first 9–12 months of life. For this reason, conservative treatment is recommended initially for these patients. Because most pediatricians are familiar with NLDO and its early treatment, patients with this condition who present to an ophthalmologist are usually older and have symptoms that have persisted beyond the normal time frame for resolution.
Conservative treatment includes lacrimal massage and use of topical antibiotics. Massage serves 2 purposes: it empties the sac, thereby reducing the opportunity for bacterial growth, and it applies hydrostatic pressure to the obstruction, which may open the duct and resolve the condition. Massage is performed by pressing over the lacrimal sac, at the medial canthus, a few times per day. This is the only location where application of external pressure on the lacrimal sac can be effective. Passing the finger along the nares, which is often mistakenly recommended by primary care providers, is not effective because the lacrimal duct is covered by bone at this site.
Topical antibiotics are often recommended if patients have significant periocular discharge. There are 3 important points with regard to topical antibiotic use in this disorder. First, the antibiotics do not cure the obstruction. They may temporarily improve the associated infection, but they do not cause the distal lacrimal membrane to resolve. Second, the infection in NLDO is due to stasis of fluid within the lacrimal sac. Therefore almost any bacteria, including normal flora, may cause infection. Most broad-spectrum antibiotics are effective in reducing the associated symptoms, so culturing the mucoid or mucopurulent material is usually not necessary. Third, antibiotic use for a few days often produces improvement, and prolonged use may not be necessary. Parents may be instructed to administer the antibiotics as needed when the amount of discharge increases.
Surgical Management
Nasolacrimal probing is one of the most common procedures performed by pediatric ophthalmologists. It is used to treat infants with NLDO whose symptoms do not resolve with age and conservative treatment. There are 2 common approaches to the surgical management of this disorder. Some ophthalmologists recommend probing at age 3–6 months in an awake infant in the office, whereas others prefer to delay treatment until age 9–12 months, at which time surgery is performed in the operating room. The advantages of early in-office probing are that it avoids general anesthesia and resolves symptoms earlier. The disadvantages are that a painful procedure is performed on an awake infant and that surgery is performed on many infants who would spontaneously improve without surgery (approximately 75%). The advantages of later surgery in the operating room are that fewer infants require treatment and that surgery is performed in a more controlled environment, in which additional procedures can be performed concurrently. Either of these approaches is acceptable.
Surgical procedures for NLDO are also discussed in BCSC Section 7, Orbit, Eyelids, and Lacrimal System.
Pediatric Eye Disease Investigator Group. A randomized trial comparing the cost-effectiveness of 2 approaches for treating unilateral nasolacrimal duct obstruction. Arch Ophthalmol. 2012; 130(12):1525–1533.
Probing
When nasolacrimal probing is to be performed in the operating room, placement of an oxymetazoline-soaked pledget beneath the inferior turbinate before surgery may decrease
intraoperative bleeding. The initial step in nasolacrimal probing is dilation of the puncta and proximal canaliculi. Punctal membranes and atretic canaliculi are sometimes not recognized until surgery. Their management is discussed earlier in this chapter. Because the lacrimal system cannot be visualized beyond the puncta, knowledge of the anatomy and normal course of the system’s structures is essential for passing lacrimal probes properly. The probes are initially inserted in the puncta, perpendicular to the eyelid. Within 1–2 mm of the eyelid margin, the canaliculi turn approximately 90°; the probes are therefore turned almost immediately and passed along the course of the canaliculi until the nasal bone is encountered on the medial side of the lacrimal sac. The probes are held flat on the patient’s face and rotated until they are almost vertical; they are then passed gently into the distal duct (Fig 19-5A). Most surgeons feel a slight popping sensation as the probe passes through the membrane causing the obstruction.
Figure 19-5 Probing for lacrimal obstruction. A, The probe is advanced through the lacrimal sac and nasolacrimal duct, in this instance via the lower canaliculus. B, A second probe introduced into the nares is used to verify the position of the probe
tip. (Courtesy of Edward L. Raab, MD.)
A wide variety of techniques are used for probing in NLDO. Most surgeons begin with a size 0 or 1 Bowman probe, and some pass successively larger probes to enlarge the distal duct. Irrigation may be performed following probing in order to verify that the system is patent. Introducing a second metal probe into the nares and making direct contact with the previously placed lacrimal probe verifies the position of the latter (Fig 19-5B). Alternatively, direct inspection with a nasal speculum and headlamp or with a nasal endoscope can determine the precise position of the probe. Infracture of the inferior turbinate may be employed to widen the area where the fluid drains beneath the inferior turbinate. The surgeon accomplishes this by placing a small periosteal elevator beneath the turbinate or by grasping it with a hemostat and then rotating the instrument.
Postoperatively, minor bleeding from the nose or into the tears commonly occurs and usually requires no treatment. Optional postoperative medications include antibiotic drops, corticosteroid drops, or both instilled 1–4 times daily for 1–2 weeks. Phenylephrine or oxymetazoline nasal spray may be used to control nasal bleeding or congestion. Because transient bacteremia can occur after probing, systemic antibiotic prophylaxis should be considered for patients with cardiac disease.
Resolution of signs after probing may not occur until 1 week or more postoperatively. Recurrence after unsuccessful probing is usually evident within 1–2 months. The success rate of properly performed initial probing for congenital NLDO exceeds 80% in infants younger than 15 months.
Significant complications of probing are rare. In some patients, mild epiphora occurs occasionally, particularly outdoors in cold weather or in conjunction with an upper respiratory tract infection. This epiphora is probably attributable to a patent but narrow lacrimal drainage channel. Usually no
additional treatment is required.
Patients with persistent symptoms following initial probing
A variety of treatment options are available for patients whose symptoms persist following initial probing. A second probing can be used in such patients, with or without infracture of the inferior turbinate.
Some surgeons employ balloon catheter dilation, intubation, or nasal endoscopy (discussed in the following subsections) during the first surgery for NLDO, but most reserve their use for patients who require a second procedure.
Balloon catheter dilation Balloon catheter dilation (BCD) is performed by passing a catheter into the distal NLD and inflating a balloon at the site of obstruction (Fig 19-6). This procedure is particularly useful for patients with diffuse, rather than localized, obstruction of the distal duct.
Figure 19-6 Balloon catheter dilation. Probe positioned in the nasolacrimal duct. The surgeon inflates the balloon. (Courtesy of
Edward L. Raab, MD.)
Intubation Intubation of the lacrimal system is usually recommended when 1 or more probings or
BCD has failed. Several methods of intubation are available. Bicanalicular intubation is performed by passing stents through the upper and lower canaliculi and recovering them in the nares. Most surgeons secure the stents in the nares by using a bolster or by suturing the stents to the nasal mucosa. Monocanalicular stents are placed by passing them through either the upper or lower canaliculus or sometimes by passing separate stents through both canaliculi.
Complications associated with stents include elongation of the lacrimal puncta, dislodging and protrusion of the stents, and corneal abrasions. In some cases, the stent can be repositioned, but early removal may be necessary.
Stents are usually left in place for 2–6 months, but shorter periods can be successful. The technique used for stent removal depends on the age of the patient, the measure employed to secure the stent, and the position of the stent (in place or partially dislodged).
Nasal endoscopy Anatomical abnormalities of the distal NLD account for some of the failures of initial probing. These abnormalities include cysts similar to those seen in infants with dacryocystoceles and flaccid mucosal membranes obstructing the distal duct. In addition, false passages may be recognized endoscopically, in which case the probe may be re-placed so that it is in the proper position. Removal of abnormal structures is performed under endoscopic guidance. Endoscopy may be performed by the ophthalmologist alone or in conjunction with an otolaryngologist.
Older children with lacrimal obstruction
Previous studies suggested that children who present with NLDO after 18–24 months of age may be less likely to show improvement following NLD probing. However, many of these studies did not account for anatomical variations of the distal NLD. Some older children with NLDO have the same membranous obstruction of the distal duct that is present in younger children with NLDO (Fig 197A). This obstruction is identified by a distinct popping sensation as the probe is passed into the distal duct. Probing in older patients with this finding has a success rate similar to that in younger children. Diffuse stenosis of the distal duct (Fig 19-7B) is another anatomical abnormality that may be found in patients with NLDO. It is identified by palpation of a tight passage occurring throughout the distal duct. Because probing is less likely to be successful when diffuse stenosis is present, BCD or stent placement (discussed earlier) should be considered in patients with this finding.
Figure 19-7 A, Typical location of membrane causing nasolacrimal duct obstruction (arrow). B, Diffuse stenosis of distal
nasolacrimal duct. (Adapted from an illustration by Christine Gralapp.)
Dacryocystorhinostomy
Dacryocystorhinostomy involves creation of a new opening between the lacrimal sac and the nasal cavity. It is a final option when the procedures described in the preceding sections are unsuccessful and NLDO persists or recurs. The decision of when to perform this procedure is affected by the severity of the signs and symptoms of obstruction.
See BCSC Section 7, Orbit, Eyelids, and Lacrimal System, for further discussion of this procedure.