Nasolacrimal duct occlusion

Veterinary advice should be sought before applying any treatment or vaccine.

Nasolacrimal Duct Occlusion

Stenosis, Blocked Tear Duct

Nasolacrimal duct occlusion (NLDO) is a blocked tear duct, which is a common eye condition in horses. NLDO can develop for a number of reasons which include:
  • Dacryoliths or cast formation, within the lacrimal sac
  • Trauma
  • Inflammatory disease
  • Tooth root disease
  • Sinus disease: Sinus disease often occurs in conjunction with, and in other instances may contribute to the development of NLD obstruction.
  • Involutional stenosis
  • Tumor
  • Congenital

NLDO usually occurs during the warmer months and presents as chronic discharge visible from one or both of the horse's eyes. Sometimes hair loss and mild swelling of the eyelid is present due to the excessive discharge, depending on how long the teat duct has been blocked. The condition isn't serious, but can attract flying insects which can lead to a secondary bacterial infection.


Chronic tearing from one or both eyes
Mild swelling of the eyelids
Hair loss where discharge as accumulated
Matting of the hair below the eye


  • History
  • Clinical signs
  • Physical exam
  • Endoscopy



Wipe eyes clean daily with sterile, soaked swabs and turn the horse out with a fly mask.
Antibiotic eye drops
Flushing the tear ducts with sterile saline, performed while the horse is sedated by your veterinarian.




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