Regional Veterinary Surgery

NASO LACRIMAL DUCT OCCLUSION

• Topical ophthalmic application of fluorescein dye and observation for its appearance at the nares confirms patency of the nasolacrimal duct on that side and is referred to as the Jones or fluorescein passage test.
• The interval required for fluorescein to appear is variable (up to 5 to 10 minutes in some normal dogs).
• In some dogs and cats, especially brachycephalic breeds, drainage from the nasolacrimal duct may occur into the posterior nasal cavity, resulting in false- negative result of the Jones test unless the mouth is also examined.

Symptoms

• Epiphora unilateral or bilateralIf there is obstruction of the duct , a naso lacrimal flushing after catheterisation is practised.
• Nasolacrimal Flush (Catheterization) is indicated for epiphora and dacryocystitis.

Procedure for indwelling nasolacrimal duct catheterization for flushing

• A monofilament nylon thread (2/0 with a smooth melted end) is passed via the superior punctum to emerge from the nose. If an obstruction is present in the sac, the duct is threaded from the nasal end, and the thread is manipulated to emerge from the superior punctum.
• Fine polyethylene (PE90), polyvinyl, or silicone tubing with a beveled end is passed over the thread. Halsted forceps are clamped behind the tubing, which is pulled from the nasal end by forceps on the thread. In horses, larger tubing is used.
• Care is taken as the tubing enters the punctum. Note: The inferior punctum may also be used if threading via this punctum was used. The tubing is pulled down the nasolacrimal duct, past any obstructions.
• The tube is sutured in place for 2 to 3 weeks. An Elizabethan collar should be considered to prevent the tubing from being dislodged.