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Basics ⬇

Basics

Definition

Abnormal overflow of the aqueous portion of the precorneal tear film.

Pathophysiology

Caused by one of three common problems:

  • Overproduction of the aqueous portion of tears (usually in response to ocular irritation).
  • Poor eyelid function secondary to eyelid malformation or deformity.
  • Blockage of the nasolacrimal drainage system.

Systems Affected

Eye and periocular skin

Signalment

See “Causes”

Signs

N/A

Causes

Overproduction of Tears Secondary to Ocular Irritants

Congenital

  • Distichiasis or trichiasis-common in young shelties, shih tzus, Lhasa apsos, cocker spaniels, miniature poodles.
  • Entropion-shar-peis, chow chows, Labrador retrievers.
  • Eyelid agenesis-domestic shorthair cats.

Acquired

  • Corneal or conjunctival foreign bodies-usually young, large-breed, active dogs.
  • Eyelid neoplasms-old dogs (all breeds).
  • Blepharitis-infectious or immune mediated.
  • Conjunctivitis-infectious or immune mediated.
  • Ulcerative keratitis.
  • Anterior uveitis.
  • Glaucoma.

Eyelid Abnormalities or Poor Eyelid Function

  • Tears never reach the nasolacrimal puncta but instead spill over the eyelid margin.
  • eyelid function does not direct tears to the medial canthus and nasolacrimal puncta.

Congenital

  • Macropalpebral fissures-brachiocephalic breeds.
  • Ectropion-Great Danes; bloodhounds; spaniels.
  • Entropion-brachycephalic dogs-medial lower eyelid; Labrador retrievers-lateral lower eyelid.

Acquired

  • Post-traumatic eyelid scarring.
  • Facial nerve paralysis.

Obstruction of the Nasolacrimal Drainage System

Congenital

  • Imperforate nasolacrimal puncta-cocker spaniels, bulldogs, poodles.
  • Ectopic nasolacrimal openings-extra openings along the side of the face ventral to the medial canthus.
  • Nasolacrimal atresia-lack of distal openings into the nose.

Acquired

  • Rhinitis or sinusitis-causes swelling adjacent to the nasolacrimal duct.
  • Trauma or fractures of the lacrimal or maxillary bones.
  • Foreign bodies-grass awns, seeds, sand, parasites.
  • Neoplasia-of the third eyelid, conjunctiva, medial eyelids, nasal cavity, maxillary bone, or periocular sinuses.
  • Dacryocystitis-inflammation of the canaliculi, lacrimal sac, or nasolacrimal ducts.

Risk Factors

  • Breeds prone to congenital eyelid abnormalities (see “Causes”).
  • Active outdoor dogs-at risk for foreign bodies.

Diagnosis ⬆ ⬇

Diagnosis

Differential Diagnosis

  • Other ocular discharges (e.g., mucous or purulent)-epiphora is a watery, serous discharge.
  • Eye-usually red when caused by overproduction of tears; quiet when secondary to impaired outflow.
  • Irritative causes and some congenital causes of obstruction-thorough ocular examination.
  • Acute onset, unilateral condition with ocular pain (blepharospasm)-usually indicates a foreign body or corneal injury.
  • Chronic, bilateral condition-usually indicates a congenital problem.
  • Facial pain, swelling, nasal discharge, or sneezing-may indicate nasal or sinus infection; may indicate obstruction from neoplasm.
  • With mucous or purulent discharge at the medial canthus-may indicate dacryocystitis.

CBC/Biochemistry/Urinalysis

N/A

Other Laboratory Tests

N/A

Imaging

  • Skull radiographs-may show a nasal, sinus, or maxillary bone lesion.
  • Dacryocystorhinography-radiopaque contrast material to help localize obstruction.
  • MRI or CT-may help localize obstruction (usually with contrast media) and characterize associated lesions.

Diagnostic Procedures

  • Bacterial culture and sensitivity testing and cytologic examination of the material-with purulent material at the medial canthus (e.g., dacryocystitis); performed before instilling any substance into the eye.
  • Topical fluorescein dye application to the eye-most physiologic test for nasolacrimal function; should be performed first (after culture); dye flows through the nasolacrimal system and reaches the external nares in approximately 10 seconds in normal dogs.
  • Nasolacrimal irrigation-see information below.
  • Rhinoscopy-with or without biopsy or bacterial culture; may be indicated if previous tests suggest a nasal or sinus lesion.
  • Surgical exploratory-may be the only way to obtain a definitive diagnosis.
  • Temporary tacking out of the lower medial eyelid with suture-may help determine whether repair of medial lower entropion or repositioning of the eyelid would reduce epiphora secondary to eyelid conformational abnormalities.

Nasolacrimal Irrigation

  • Confirms obstruction.
  • May dislodge foreign material.
  • A nasolacrimal cannula is inserted into the upper nasolacrimal punctum.
  • Eyewash is irrigated through the cannula-if fluid does not exit the lower nasolacrimal punctum, the obstruction is in the upper or lower canaliculi, the nasolacrimal sac, or the lower punctum (imperforate).
  • Lower punctum is manually obstructed-if flushed fluid does not exit the external nares, the obstruction is in the nasolacrimal duct or at its distal opening (atresia or blockage from a nasal sinus lesion).

Treatment ⬆ ⬇

Treatment

Surgical Considerations

Imperforate Puncta

  • Surgical opening of the puncta is indicated.
  • If one of the puncta is patent (usually the upper punctum), flushing eyewash through the upper opening will cause “tenting” of the conjunctiva at the site of the lower punctum. Place patient under topical or general anesthesia. Grasp conjunctiva overlying the lower canaliculi with forceps and cut with scissors to leave a patent punctum. Puncta closed by conjunctival scarring (symblepharon) caused by severe conjunctivitis (e.g., herpesvirus conjunctivitis in cats)-use same procedure. Recurrent disease-may be necessary to suture Silastic tubing in place to prevent stricture formation.

Obstructed or Obliterated Distal Nasolacrimal Duct

  • Dacryocystorhinotomy or conjunctivorhinostomy-create an opening to drain the tears into the nasal cavity.
  • See “Suggested Reading” for surgical technique.

Medications ⬆ ⬇

Medications

Drug(s) Of Choice

  • Topical broad-spectrum antibiotic ophthalmic solutions-while awaiting diagnostic test results (e.g., bacterial culture and sensitivity testing; diagnostic radiographs); q4–6h; may try neomycin, gramicidin, polymyxin B triple ophthalmic antibiotic solution, or ophthalmic ciprofloxacin solution.
  • Dacryocystitis-based on bacterial culture and sensitivity test results; continued for at least 21 days.

Contraindications

  • Topical corticosteroids or antibiotic-corticosteroid combinations-avoid unless a definitive diagnosis has been made.
  • Topical corticosteroids-never use if the cornea retains fluorescein stain.

Precautions

N/A

Possible Interactions

N/A

Alternative Drug(s)

Tetracycline 5 mg/kg PO q24h; may help reduce idiopathic tear staining of the periocular facial hair; staining recurs when the drug is discontinued.

Follow-Up ⬆ ⬇

Follow-Up

Patient Monitoring

Dacryocystitis

  • Reevaluate every 7 days until the condition is resolved.
  • Continue treatment for at least 7 days after resolution of clinical signs to help prevent recurrence.
  • Problem persists more than 7–10 days with treatment or recurs soon after cessation of treatment-indicates a foreign body or nidus of persistent infection; requires further diagnostics (e.g., dacryocystorhinography).
  • Nasolacrimal catheter.
  • Commonly required for persistent dacryocystitis.
  • Maintains patency of the duct and prevents structuring.
  • Catheter-Silastic or polyethylene (PE90) tubing; left in place 2–4 weeks.
  • Procedure-pass 2-0 nylon via the upper punctum and thread it through the nasolacrimal duct to exit the external nares; pass tubing retrograde over the suture; suture the upper and lower portions of the tubing to the face.
  • Most dogs tolerate the tubing well, however, an Elizabethan collar may be needed to prevent self-trauma.
  • Continue topical antibiotics as before.

Dacryocystorhinotomy/Conjunctivo-Rhinostomy

  • Tubing-reevaluate every 7 days to ensure it remains intact; may need to resuture if it becomes loosened or dislodged.
  • After tubing has been removed-reevaluate in 14 days; for this and future examinations, place fluorescein on the eye and check nasolacrimal patency by examining the external nares for fluorescein; may evaluate the nasolacrimal system further by cannulating and flushing with eyewash.
  • Dacryocystorhinography contrast study-repeated 3–4 months after surgery to evaluate size of the nasal opening; repeated for recurrence or with no nasolacrimal fluorescein drainage.

Possible Complications

Recurrence-most common complication; caused by recurrence of ocular irritation (e.g., corneal ulceration, distichiasis, entropion), recurrence of dacryocystitis, or closure of the dacryocystorhinotomy or conjunctivorhinostomy openings into the nasal cavity.

Miscellaneous ⬆

Miscellaneous

Associated Conditions

  • Chronic conjunctivitis-cats
  • Chronic conjunctivitis-dogs
  • Recurrent eye “infections”
  • Moist dermatitis (hot spots) ventral to the medial canthus
  • Nasal discharge

Age-Related Factors

N/A

Zoonotic

N/A

Pregnancy/Fertility/Breeding

N/A

Abbreviations

  • CT = computed tomography
  • MRI = magnetic resonance imaging

Suggested Reading

Giuliano EA. Diseases and surgery of the canine nasolacrimal system. In: Gelatt KN, Gilger BC, Kern T, eds., Veterinary Ophthalmology, 5th ed. Ames, IA: Wiley-Blackwell, 2013, pp. 912–944.

Miller PE. Lacrimal system. In: Maggs DJ, Miller PE, Ofri R, Slatter's Fundamentals of Veterinary Ophthalmology, 5th ed. St. Louis, MO: Elsevier, 2013, pp. 165–183.

Author Brian C. Gilger

Consulting Editor Paul E. Miller

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