AUTHOR AND EDITOR INFORMATION

Section 1 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Multimedia
• References

INTRODUCTION

Section 2 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Multimedia
• References

Background

Epiphora is defined as the overflow of tears. The clinical spectrum of epiphora ranges from the occasionally bothersome trickle to the chronically irritating overflow. Epiphora is caused by a disruption in the balance between tear production and drainage. The lacrimal drainage system is a continuous and complex membranous channel whose function is dependent on the interaction of anatomy and physiology.

When faced with a patient who complains of tearing, the first step is to determine whether the epiphora is caused by an increase in lacrimation or a decrease in tear drainage. Trichiasis, superficial foreign bodies, eyelid malpositions, diseases of the eyelid margins, tear deficiency or instability, and cranial nerve V irritation may cause an abnormal increase in tear production. In the absence of these conditions, abnormality in tear drainage is the most likely cause.

Abnormalities of tear drainage may be subdivided further into functional and anatomical. Functional failure is related to poor lacrimal pump function, which may be due to a displaced punctum, eyelid laxity, weak orbicularis, or cranial nerve VII palsy. Anatomical obstruction may occur at any point along the lacrimal drainage pathway and may be congenital or acquired. Congenital obstructions tend to produce symptoms during the neonatal period and are the subject of another article.

Classification of nasolacrimal drainage obstruction (NLDO): The 2 types of acquired nasolacrimal drainage obstructions are primary and secondary. In 1986, Linberg and McCormick coined the term primary acquired nasolacrimal duct obstruction (PANDO) to describe an entity of nasolacrimal duct obstruction caused by inflammation or fibrosis without any precipitating cause. Bartley proposed an etiologic classification system for secondary acquired lacrimal drainage obstruction (SALDO) based on published cases.

Pathophysiology

PANDO is more common in middle-aged and elderly females. Using CT scans, Groessl, Sires, and Lemke demonstrated that women have significantly smaller dimensions in the lower nasolacrimal fossa and middle nasolacrimal duct. They noted that changes in the anteroposterior dimensions of the bony nasolacrimal canal coincide with osteoporotic changes throughout the body. These quantitative measurements may help explain the higher incidence of PANDO in women. Others have suggested menstrual and hormonal fluctuations and a heightened immune status as factors that may contribute to the disease process. These may explain the prevalence in middle-aged and elderly females. Hormonal changes that bring about a generalized de-epithelialization in the body may cause the same within the lacrimal sac and duct. An already narrow lacrimal fossa in women predispose them to obstruction by the sloughed off debris.

The general categories of causes of SALDO include infectious, inflammatory, neoplastic, traumatic, and mechanical. Bacteria, viruses, fungi, and parasites have been implicated as causes of infectious lacrimal drainage obstruction. Bacteria such as Actinomyces, Propionibacterium, Fusobacterium, Bacteroides, Mycobacterium, and Chlamydia species have been associated with lacrimal drainage obstruction.

Other bacteria include Nocardia, Enterobacter, Aeromonas, Treponema pallidum, and Staphylococcus aureus. Viral causes of obstruction most commonly are seen with herpetic infection (eg, herpes simplex, herpes zoster, chickenpox, epidemic keratoconjunctivitis). The obstruction is due to the damage of the substantia propria of the canalicular elastic tissue and/or the adherence of the inflammatory membranes to the raw epithelial surface of the canaliculus.

Fungi may obstruct lacrimal passages by forming a stone (dacryolith) or cast. Species associated with obstruction are Aspergillus, Candida, Pityrosporum, and Trichophyton. Parasitic obstruction is rare but is reported in patients infected with Ascaris lumbricoides, which enters the lacrimal system through the valve of Hasner.

Inflammation may be endogenous or exogenous in origin. Wegener granulomatosis and sarcoidosis are 2 examples of conditions that lead to obstruction due to progressive inflammation within the nasal and lacrimal sac mucosa. Other endogenously arising inflammations associated with lacrimal obstruction are cicatricial pemphigoid, sinus histiocytosis, Kawasaki disease, and scleroderma.

A study published in Ophthalmic Plastic and Reconstructive Surgery in May 2003 presented clinicopathologic findings from lacrimal sac biopsy specimens obtained during dacryocystorhinostomy (DCR). Their data revealed the following, in decreasing order of frequency: nongranulomatous inflammation (85.1%); granulomatous inflammation consistent with sarcoidosis (2.1%); lymphoma (1.9%); papilloma (1.11%); lymphoplasmacytic infiltrate (1.1%); transitional cell carcinoma (0.5%); and single cases of adenocarcinoma, undifferentiated carcinoma, granular cell tumor, plasmacytoma, and leukemic infiltrate. They concluded that nongranulomatous inflammation consistent with chronic dacryocystitis is the most common diagnosis in lacrimal sac specimens obtained at DCR. Neoplasms resulting in chronic nasolacrimal duct obstruction occurred in 4.6% of cases and were unsuspected before surgery in 2.1% of patients.

Exogenous causes of cicatricial lacrimal drainage obstruction are eye drops, radiation, systemic chemotherapy, and bone marrow transplantation. Ophthalmic medications are the most common cause of iatrogenic punctal and canalicular scarring. Radiotherapy of the medial canthal area may cause a sufficiently severe inflammatory reaction to lead to punctal stenosis, although published reports do not agree on the amount of radiation. Systemic chemotherapy with 5-fluorouracil (5-FU) has been known to occlude the puncta and canaliculi, although the incidence has declined since oncologic regimens today use much lower doses for shorter durations.

The use of I(131) for thyroid carcinoma is associated with a 3.4% incidence of documented NLDO and an overall 4.6% incidence of documented or suspected obstruction.

Canalicular and nasolacrimal duct obstruction is a common adverse effect of weekly docetaxel therapy used for metastatic breast cancer and non-small cell lung cancer.

Neoplasms may cause lacrimal obstruction by primary growth, secondary spread, or metastatic spread. Primary neoplasms may arise in the puncta, canaliculi, lacrimal sac, or nasolacrimal duct. Secondary spread from nearby tissues is more common than primary tumors. They are most commonly eyelid cancers (eg, basal cell carcinoma, squamous cell carcinoma), although spread from the maxillary antrum and the nasopharynx also have been reported. Recent studies have documented oncocytoma and cylindroma from direct extension. Metastatic spread, an extremely rare phenomenon, has been reported with primary sites from the breast and prostate.

Trauma may be iatrogenic in the case of scarring of the lacrimal passage after overly aggressive lacrimal probing. Iatrogenic causes of NLDO also may follow orbital decompression surgery, paranasal, nasal, and craniofacial procedures. Non-iatrogenic traumatic causes are either blunt or sharp and most commonly involve the canaliculus, lacrimal sac, and nasolacrimal duct.

Posttraumatic dacryostenosis was found to have a frequent association with delayed treatment of facial fracture repair or bone loss in the lacrimal district.

Mechanical lacrimal drainage obstructions may be due to intraluminal foreign bodies, such as dacryoliths or casts. These may be caused by infection (eg, Actinomyces, Candida) as well as long-term administration of topical medications. Mechanical obstruction also may be caused by external compression from rhinoliths, nasal foreign bodies, or mucoceles.

Dentigerous cyst in the maxillary sinus has been reported to have caused nasolacrimal duct obstruction.

Frequency

United States

This condition is relatively common, but the exact frequency is not known.

Mortality/Morbidity

Epiphora can be a nuisance, but, untreated, nasolacrimal duct obstruction can cause significant problems.

Sex

• PANDO is more prevalent in women. Theories regarding this predilection in women are discussed in Pathophysiology.
• No gender predilection of SALDO exists.

Age

• PANDO most commonly is diagnosed in middle-aged women. Previous studies have noted a high incidence of PANDO in individuals aged 50-70 years.

CLINICAL

Section 3 of 10  

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• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Multimedia
• References

History

• Symptoms
  • Epiphora, mucoid, or purulent discharge
  • Recurrent dacryocystitis, recurrent conjunctivitis or ocular pemphigus
  • Painful, swelling medial canthus
  • Bloody tears
  • Epistaxis (nasal, sinus, or lacrimal sac tumor)
• Past ocular history
• • Previous eye surgery (DCR)
  • Lid surgery
  • Glaucoma (antiglaucoma medications)
  • Use of other topical medications
• Past medical history
• • Lymphoma, Wegener granulomatosis
  • Sarcoidosis
  • Ocular cicatricial pemphigoid
  • Kawasaki disease
  • Scleroderma
  • Sinus histiocytosis
  • Previous radiation treatment to medial canthal area systemic chemotherapy with 5-FU
  • Parasitic infection
  • Facial trauma
  • Previous nasal or sinus surgery

Physical

• Gross observations include the following:
• • Overflow of tears
  • Fluctuant tender mass over lacrimal sac area or medial canthal area
  • Mucoid or purulent eye discharge - Significantly distended sac may not regurgitate with pressure due to the functional valve of Rosenmüller
  • Regurgitation test - Mucoid reflux with lacrimal massage indicates lower system obstruction.
• Slit lamp findings include the following:
• • Tear meniscus height enhanced by fluorescein - Meniscus height greater than 2 mm
  • Punctal stenosis
  • Canaliculitis - Canalicular fullness and creamy pus when canaliculus is pressed
  • Expression of concretions from punctum
  • Pouting punctum with purulent material at opening

Causes

• PANDO - Idiopathic inflammation and fibrosis of nasolacrimal duct, resulting in partial stenosis or complete obliteration of duct lumen
• SALDO
• • Infectious
    • Bacteria
    • Viruses
    • Fungi
    • Parasites
  • Inflammatory
    • Exogenous
    • Endogenous
  • Neoplastic
    • Primary
    • Secondary
    • Metastatic
  • Traumatic
    • Idiopathic
    • Nonidiopathic
  • Mechanical
    • Intraluminal foreign body
    • External compression/occlusion

DIFFERENTIALS

Section 4 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Multimedia
• References

WORKUP

Section 5 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Multimedia
• References

Lab Studies

• Send lacrimal discharge for the following studies (depending on suspected etiologies):
• • Gram stain/Giemsa stain
  • Cultures and sensitivities
  • KOH (suspected fungal infection)
  • Anticytoplasmic antibodies (Wegener granulomatosis) - Monitor disease activity

Imaging Studies

• Dacryocystography
• • Visualization of anatomic details of the lacrimal drainage system using contrast material
  • Visual localization of the site of obstruction may help determine the surgical plan.
• Dacryoscintigraphy
• • More sensitive and less invasive method of lacrimal system imaging
  • More sensitive for incomplete blocks of the upper drainage system
  • Functional lacrimal duct obstruction is easily diagnosed with dacryoscintigraphy. It may be classified by types of obstruction to predict postoperative results of silicone tube insertion.
    • Class I - Delayed secretion in the distal nasolacrimal duct
    • Class II - Delays in the proximal nasolacrimal duct
    • Class III - Delayed secretion from the prelacrimal sac to the lacrimal sac
  • Prelacrimal sac obstructions, in particular, may achieve better operative results with adjuvant treatments in addition to silicone tube insertion.
  • Does not provide as much detailed anatomic imaging as contrast DCG
• Computed tomography scan
• • Use if suspecting traumatic, neoplastic, or mechanical causes of obstruction
  • Useful for diagnosis and preoperative surgical planning
• Nasal endoscopy - Used for postoperative evaluation of DCR and for DCR using the endonasal approach
• Gadolinium-enhanced magnetic resonance dacryocystography
• • The overall sensitivity of magnetic resonance (MR) in detecting obstruction was 100%. MR helped to determine the canalicular and ductal obstruction in 100% of patients and the saccular obstruction in 80% of patients.
  • The authors of this study concluded that three-dimensional (3D) fast spoiled gradient-recalled (FSGR) technique for MR dacryocystography is a reliable and noninvasive method in the evaluation of the obstruction level in the lacrimal system in patients with epiphora.

Other Tests

• Tear production measurement to rule out tear deficiency or instability as the cause of possible reflex tearing
• Schirmer test
• • Without topical anesthetic (stimulated tear production): Normal measurement is 10-30 mm wetting of Schirmer strip after 5 minutes.
  • With topical anesthesia (basic secretion): Normal measurement is greater than 5 mm of wetting of Schirmer strip paper after 5 minutes.
• Tear break-up time test to rule out tear instability: Normal break-up time is 15-30 seconds. A time of 10 seconds or less is considered distinctly abnormal.
• Fluorescein dye disappearance test
• • A positive result is indicated by +2 to +4 residual fluorescein 5 minutes after instillation.
  • Positive results indicate a partial or complete obstruction, or pump failure.
  • This test is simple and effective as a screening tool.
  • The shortcomings are inability to distinguish between physiologic and anatomic causes of drainage dysfunction, inability to distinguish between upper and lower abnormality, and false-positive results.
• Lacrimal irrigation
• • Reflux of irrigating fluid in the opposite/upper punctum demonstrates patency of the canalicular system but suggests obstruction in the distal drainage system.
  • Lacrimal irrigation occasionally may be therapeutic by dislodging an obstructing stone or concretion or widening a partially stenosed passage.
  • Rarely, adult patients are completely relieved of symptoms after nasolacrimal probing and irrigation; others are only relieved temporarily or not at all.
• Probing of canaliculi
• • When the irrigation test indicates obstruction, probing is used in an attempt to palpate or localize the site of obstruction.
  • The location of canalicular obstruction may be located, or degree of stenosis may be estimated.
• Jones dye tests
• • Jones I: Dye is instilled in patient's eye, and they are asked to blow their nose after 5 minutes.
    • Presence of dye indicates a patent system and normal physiologic function.
    • Absence of dye indicates the following 3 possibilities:false-negative result, physiologic dysfunction, or anatomic obstruction.
  • Jones II: Patients' lacrimal drainage system is irrigated after a negative Jones I, and they are asked to expel any drainage from their pharynx.
    • Presence of dye indicates partial block at lower sac or duct
    • Presence of saline indicates punctal or canalicular stenosis
    • Regurgitation indicates the following: complete NLDO or complete common canaliculus block.
  • High level of false results from Jones test
• Microreflux test
  • Screening test for PANDO
  • Positive test - Reflux of fluorescein-stained tears from the inferior punctum after counterclockwise lacrimal sac massage
  • Sensitivity of 97%
  • Specificity of 95%
• Hornblass saccharine test
• • Instill saccharine drops in one eye and chloramphenicol eye drops in the other several minutes later.
  • The ability of the patient to detect the sweet taste of the saccharine and the bitter taste of the chloramphenicol denotes a patent lacrimal system.
  • False-negative results are possible.

TREATMENT

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Medical Care

• Type of antibiotic depends on suspected infecting agent or results of cultures and sensitivities.
• Topical antibiotics with lacrimal massage may be adequate for early infections.
• Systemic antibiotics may be necessary for more chronic or severe infections such as those causing dacryocystitis, canaliculitis, or preseptal cellulitis (may progress to orbital abscesses).
• Although sensitive to penicillin, Actinomyces organisms usually require complete removal of the canalicular stones for complete treatment.

Surgical Care

• External DCR
• • Criterion standard of lacrimal bypass surgeries
  • Success rates up to 95%
  • Facilitates identification and removal of dacryoliths and lacrimal sac tumors; also allows for biopsy of every lacrimal sac
  • Requires skin incision
  • Creates a communication between the lacrimal sac and nasal cavity, bypassing the obstructed nasolacrimal duct
• Endoscopic mechanical/nonlaser DCR
  • Involves the creation of a large ostium and construction of nasal and lacrimal sac mucosal flaps
  • Difficult to make definite evidence-based determinations about the relative efficacy of endonasal and external DCR because of the deficiencies in the reported literature
  • Available data suggest that endonasal DCR may be a viable option for the correction of acquired nasolacrimal duct obstruction and complex forms of congenital dacryostenosis in selected patients.
  • May be indicated on a primary basis or as revisional surgery following failed external or endonasal DCR
  • Some studies comparing endonasal DCR with external DCR suggested lower success rates in the endonasal group. Other studies yielded success rates comparable with or exceeding those of external surgery.
  • Complications of endonasal DCR do not generally appear to be greater in frequency or magnitude than those associated with external DCR.
  • Disadvantages of endonasal DCR include the preferred use of general anesthesia by many surgeons, the high cost of expensive equipment and instrumentation, and the relatively steep learning curve for this procedure.
  • Depending on the preference of the surgeon, more postoperative care may be required for patients undergoing endonasal DCR than external DCR. In one study, the success rate of 93.5% compares favorably with that of standard external DCR (95.8%).
  • Anatomical success rate (91%) compares favorably with the success rate of other techniques for endonasal DCR and is also similar to the success of external DCR.
  • Experience in endoscopic nasal surgery is important, as other ancillary procedures may be required within the nose at the time of surgery.
• Endoscopic laser DCR
  • KTP laser is used.
  • In one recent study, the success rate in the endonasal group improved from 50% in the first 38 cases to 79% in the last 38 cases, thereby demonstrating a learning curve.
• Endoscopic laser-assisted DCR
  • Advantages
    • No skin incision
    • Less bleeding
    • Faster recovery
  • Approaches
    • Endocanalicular
    • Trans-conjunctival
    • Endoscopic nasal
• Conjunctivodacryocystorhinostomy
• • Conjunctivodacryocystorhinostomy (CDCR) is performed in cases of flaccid canaliculi, paralysis of lacrimal pump, absence or obliteration of canaliculi, when site of obstruction is proximal (punctum, canaliculi, lacrimal sac), congenital malformations, cicatricial conjunctival disease, chemical burns, irradiation, and tumors of the lacrimal sac.
  • The procedure uses a Pyrex Jones tube, which serves as a conduit between the medial conjunctival cul-de-sac and the nasal cavity.
  • Adjunctive use of mitomycin-C during DCR procedures significantly increases the success rate without adverse effects.
• Balloon catheter dilatation
• • The use of balloon catheter dilation for the treatment of adults with partial nasolacrimal duct obstruction and for children with congenital nasolacrimal duct obstruction has been described with good results in patients without active infection.
  • This treatment is effective for congenital nasolacrimal duct obstruction.
  • This treatment is highly successful in older children who failed previous probing.
  • Success in children older than 24 months is 82.9%. Success in children younger than 24 months is 65.4%.
  • Balloon catheter dilatation is more effective than simple probing for older children with nasolacrimal duct obstruction because of stenosis that extends along the distal nasolacrimal duct.
  • No significant advantage exists over simple nasolacrimal duct probing in patients with typical membranous obstruction at the Hasner valve.
  • Endoscopically assisted balloon dacryoplasty has been shown as a treatment for incomplete NLDOs to provide substantial improvement or even complete relief.
• Stents may be used as a first-line treatment for epiphora.
  • Polyurethane stents
    • Low success rate for the treatment of PANDO
    • May induce inflammation and fibrous tissue formation
    • May cause further difficulties in subsequent lacrimal surgeries
    • Does not appear to be an efficacious therapeutic option for treating epiphora caused by postsaccal obstruction
  • Silicone: Double bicanalicular silicone intubation with the placement of 2 loops of silicone tubing through the nasolacrimal duct for the treatment of persistent nasolacrimal duct obstruction in children is an effective alternative to DCR in selected children who have failed conventional therapies.

MEDICATION

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The definitive treatment is mainly surgical. Medical therapy is necessary in cases of canaliculitis, cellulitis, or dacryocystitis secondary to the obstruction. See Dacryocystitis and Cellulitis, Preseptal regarding medical treatment.

FOLLOW-UP

Section 8 of 10  

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• Medication
• Follow-up
• Multimedia
• References

Further Inpatient Care

• DCR may be performed as an outpatient procedure, especially if performed with a laser; there is less bleeding and faster recovery.

Further Outpatient Care

• After the DCR, patients are given antibiotic eye drops and nasal decongestant spray. The silicone stent tube is removed after 3 months. In some situations (ie, Wegener granulomatosis), the stents may need to be retained indefinitely.

In/Out Patient Meds

• Antibiotic/steroid eye drops, such as tobramycin/dexamethasone combination eye drops, are prescribed postoperatively for use 2-3 times per day for 2-3 weeks as prophylaxis to infection and to decrease postoperative inflammation.
• Nasal decongestant sprays are prescribed postoperatively for use 2-3 times per day for 2-3 weeks.

Complications

• Excessive bleeding (epistaxis)
• Poor/delayed wound healing
• Wound infection
• Accidental removal of tube/stent by the patient

Prognosis

• Both external and endoscopic laser DCR have success rates higher than 90%; external DCR is slightly more successful.

Patient Education

• Explain the following to the patient:
• • Normal lacrimal drainage process
  • Obstruction of lacrimal drainage passageway
  • Possible diagnostic tests that may be necessary to evaluate the condition and their possible results
  • Treatment protocols and options
  • If surgery is necessary, discuss the prognosis and possible intraoperative and postoperative complications.

MULTIMEDIA

Section 9 of 10  

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• Follow-up
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Media file 1:  Dacryocystitis of the left nasolacrimal system.
	View Full Size Image
Media type:  Photo

Media file 2:  Dacryocystogram. A patent nasolacrimal system on the right side of a patient and a blocked system on the contralateral side at the level of the nasolacrimal duct.
	View Full Size Image
Media type:  X-RAY

REFERENCES

Section 10 of 10

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
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• Follow-up
• Multimedia
• References

• Anderson NG, Wojno TH, Grossniklaus HE. Clinicopathologic findings from lacrimal sac biopsy specimens obtained during dacryocystorhinostomy. Ophthal Plast Reconstr Surg. May 2003;19(3):173-6. [Medline].
• Bajaj MS, Mahindrakar A, Pushker N. Dentigerous cyst in the maxillary sinus: a rare cause of nasolacrimal obstruction. Orbit. Dec 2003;22(4):289-92. [Medline].
• Bartley GB. Acquired lacrimal drainage obstruction: an etiologic classification system, case reports, and a review of the literature. Part 1. Ophthal Plast Reconstr Surg. 1992;8(4):237-42. [Medline].
• Bartley GB. Acquired lacrimal drainage obstruction: an etiologic classification system, case reports, and a review of the literature. Part 2. Ophthal Plast Reconstr Surg. 1992;8(4):243-9. [Medline].
• Bartley GB. Acquired lacrimal drainage obstruction: an etiologic classification system, case reports, and a review of the literature. Part 3. Ophthal Plast Reconstr Surg. 1993;9(1):11-26. [Medline].
• Becelli R, Renzi G, Mannino G. Posttraumatic obstruction of lacrimal pathways: a retrospective analysis of 58 consecutive naso-orbitoethmoid fractures. J Craniofac Surg. Jan 2004;15(1):29-33. [Medline].
• Burns JA, Morgenstern KE, Cahill KV. Nasolacrimal obstruction secondary to I(131) therapy. Ophthal Plast Reconstr Surg. Mar 2004;20(2):126-9. [Medline].
• Camara JG, Bengzon AU, Henson RD. The safety and efficacy of mitomycin C in endonasal endoscopic laser-assisted dacryocystorhinostomy. Ophthal Plast Reconstr Surg. Mar 2000;16(2):114-8. [Medline].
• Camara JG, Santiago MD, Rodriguez RE, et al. The Micro-Reflux Test: a new test to evaluate nasolacrimal duct obstruction. Ophthalmology. Dec 1999;106(12):2319-21. [Medline].
• Camara JG, Santiago MD. Success rate of endoscopic laser-assisted dacryocystorhinostomy. Ophthalmology. Mar 1999;106(3):441-2. [Medline].
• Couch SM, White WL. Endoscopically assisted balloon dacryoplasty treatment of incomplete nasolacrimal duct obstruction. Ophthalmology. Mar 2004;111(3):585-9. [Medline].
• Dolman PJ. Comparison of external dacryocystorhinostomy with nonlaser endonasal dacryocystorhinostomy. Ophthalmology. Jan 2003;110(1):78-84. [Medline].
• Esmaeli B, Hidaji L, Adinin RB. Blockage of the lacrimal drainage apparatus as a side effect of docetaxel therapy. Cancer. Aug 1 2003;98(3):504-7. [Medline].
• Groessl SA, Sires BS, Lemke BN. An anatomical basis for primary acquired nasolacrimal duct obstruction. Arch Ophthalmol. Jan 1997;115(1):71-4. [Medline].
• Karagulle T, Erden A, Erden I, Zilelioglu G. Nasolacrimal system: evaluation with gadolinium-enhanced MR dacryocystography with a three-dimensional fast spoiled gradient-recalled technique. Eur Radiol. Sep 2002;12(9):2343-8. [Medline].
• Katowitz JA, Low JE. Lacrimal surgery. In: Duane's Ophthalmology [book on CD-ROM]. 1998;Vol 5:Chapter 79.
• Kloos RT, Duvuuri V, Jhiang SM. et al. Nasolacrimal drainage system obstruction from radioactive iodine therapy for thyroid carcinoma. J Clin Endocrinol Metab. Dec 2002;87(12):5817-20. [Medline].
• Linberg JV, McCormick SA. Primary acquired nasolacrimal duct obstruction. A clinicopathologic report and biopsy technique. Ophthalmology. Aug 1986;93(8):1055-63. [Medline].
• Lueder GT. Endoscopic treatment of intranasal abnormalities associated with nasolacrimal duct obstruction. J AAPOS. Apr 2004;8(2):128-32. [Medline].
• Lueder GT. Balloon catheter dilation for treatment of older children with nasolacrimal duct obstruction. Arch Ophthalmol. Dec 2002;120(12):1685-8. [Medline].
• Mauffray RO, Hassan AS, Elner VM. Double silicone intubation as treatment for persistent congenital nasolacrimal duct obstruction. Ophthal Plast Reconstr Surg. Jan 2004;20(1):44-9. [Medline].
• Mirza S, Al-Barmani A, Douglas SA. et al. A retrospective comparison of endonasal KTP laser dacryocystorhinostomy versus external dacryocystorhinostomy. Clin Otolaryngol Allied Sci. Oct 2002;27(5):347-51. [Medline].
• Nguyen LK, Linberg JV. Evaluation of the lacrimal system. In: Surgery of the eyelid, orbit, and lacrimal system. American Academy of Ophthalmology. 1995;3:254-69.
• Ozturk S, Konuk O, Ilgit ET, et al. Outcome of patients with nasolacrimal polyurethane stent implantation: do they keep tearing?. Ophthal Plast Reconstr Surg. Mar 2004;20(2):130-5. [Medline].
• Paul L, Pinto I, Vicente JM. Treatment of complete obstruction of the nasolacrimal system by temporary placement of nasolacrimal polyurethane stents: preliminary results. Clin Radiol. Nov 2003;58(11):876-82. [Medline].
• Shepler TR, Sherman SI, Faustina MM, et al. Nasolacrimal duct obstruction associated with radioactive iodine therapy for thyroid carcinoma. Ophthal Plast Reconstr Surg. Nov 2003;19(6):479-81. [Medline].
• Tao S, Meyer DR, Simon JW, et al. Success of balloon catheter dilatation as a primary or secondary procedure for congenital nasolacrimal duct obstruction. Ophthalmology. Nov 2002;109(11):2108-11. [Medline].
• Tsirbas A, Davis G, Wormald PJ. Mechanical endonasal dacryocystorhinostomy versus external dacryocystorhinostomy. Ophthal Plast Reconstr Surg. Jan 2004;20(1):50-6. [Medline].
• Tsirbas A, Wormald PJ. Endonasal dacryocystorhinostomy with mucosal flaps. Am J Ophthalmol. Jan 2003;135(1):76-83. [Medline].
• Wobig JL, Dailey RA. Surgery of the Lacrimal System. In: Surgery of the eyelid, orbit, and lacrimal system. American Academy of Ophthalmology. 1995;3:270-87.
• Woog JJ, Kennedy RH, Custer PL, et al. Endonasal dacryocystorhinostomy: a report by the American Academy of Ophthalmology. Ophthalmology. Dec 2001;108(12):2369-77. [Medline].
• de Bree R, Scheeren RA, Kummer A, Tiwari RM. Nasolacrimal duct obstruction caused by an oncocytoma. Rhinology. Sep 2002;40(3):165-7. [Medline].

Article Last Updated: May 9, 2006