Q. My horse has a clogged tear duct. Our veterinarian tried to blow it out with saline, but couldn’t. We are treating her with antibiotic drops, but it doesn’t seem to be improving it. She has a "swelling" on her cheek bone area, and it seems to be progressing up toward her eye. What other treatments are available? Is there a surgical procedure and, if so, would it be a realistic option? Are there any consequences of doing nothing further?

Sue, via e-mail

A. It is likely that this horse has a dacryocystitis-causing tear duct obstruction. Dacryocystitis is inflammation of the lacrimal sac and nasolacrimal duct (the tear duct at the nostril), and it is seen frequently in horses.

Dacryocystitis can develop as a primary problem or be secondary to duct obstruction. Eyelid puncta atresia (no opening in the lacrimal duct at the eyelid), nasolacrimal duct agenesis (incomplete duct development), and nasal puncta atresia (no opening in the nasolacrimal duct, the part at the nostril) are congenital abnormalities that can result in severe dacryocystitis. There are many potential causes of acquired obstruction of the nasolacrimal system (fractures, foreign bodies, neoplasias or tumors, granulomas, or sinusitis), although often an underlying cause cannot be determined