Your dog’s tear duct drains tears produced to lubricate the surface of the eye to the nose. It is referred to as the naso-lacrimal duct and carries tears through the bones into the nasal passage. Tears are required to continuously flush the eye surface of bacteria and debris. If the naso-lacrimal duct becomes blocked, does not open properly, or becomes inflamed or infected, it does not drain tears properly, causing tears to spill down your dog’s face. 

There are several treatments that can be used to unblock a tear duct and restore functioning. The most commonly used is to flush the tear duct to remove blockage, clear debris, or remove infected materials. This procedure should be performed by your veterinarian, usually under sedation or with general anesthetic. As the tear duct is an extremely delicate structure located at the corner of your dog’s eye, a veterinarian with ophthalmic training is recommended for nasolacrimal duct flushing. 

As the naso-lacrimal duct is a tiny, delicate structure, your dog will need to be immobilized prior to flushing of the tear duct so they do not inadvertently move during the procedure. Your dog will be sedated or put under general anaesthetic to ensure they will not move during the flushing procedure. If general anesthesia is required, you will need to fast your dog from food prior to the procedure. A dye may be injected into the eye and radiographs conducted prior to the procedure to locate the obstruction and determine if surgical intervention is warranted or if flushing is likely to clear the obstruction. Flushing of the tear duct is usually the first treatment of choice. Antibiotic will be administered in the form of eye drops. The eyelid is pulled out and a small catheter, or cannula, is inserted into the entrance to the tear duct. Sterile solution is injected with a syringe through the tear duct, gently, under very low pressure. Material and mucous is usually flushed out this way and removed or cleared so as not to contaminate the eye area. The procedure may need to be repeated in a few weeks if the duct is not completely cleared with the initial procedure, which is not uncommon. Your dog is put into recovery and monitored while anesthesia and sedation wears off.

Fushing of the naso-lacrimal duct is the first procedure attempted to clear blocked tear ducts. It is the least invasive and is usually successful at resolving the condition without further intervention. Due to the delicate nature of the structures involved, complications and recurrence of blockage can occur, requiring repeated flushing procedures or medication and surgery in some cases.

After flushing, you may be required to instill antibiotic eye drops or other medications into your dog's eyes. Follow your veterinarian's instructions with regard to eye medications. Observe the eye for the cessation of epiphora or any complications such as signs of infection or increased inflammation. If tear duct blockage persists or complications arise, contact your veterinarian immediately. 

Unsightly tear stains can be removed with several commercially available products. A diet free from carbohydrates may assist in healing of tear ducts where fungal or bacterial infection or immune system disorder were factors.

The cost of flushing the nasolacrimal duct includes administration of sedation or anesthesia, which contributes to the cost of the procedure. Also, your veterinarian’s ophthalmic training may contribute to pricing. The cost of tear duct flushing ranges from $200 to $500 or more and may include both tear ducts if necessary.

If too much pressure is used or if obstruction does not dislodge and continued pressure is applied, your dog's tear duct is subject to rupture. This procedure must be conducted with expertise and care to prevent damage to delicate eye structures.

Persistent blockage and infection can occur, and when chronic conditions present, further medical intervention including surgical procedures to clear ducts may be required.

Avoid exposing your dog and their eyes to airborne dust and debris that can accumulate in naso-lacrimal ducts and cause inflammation, infection, and blockage. Seek veterinary attention as soon as possible for eye conditions, before chronic complications become an issue.