What is it?Rabbits have a single tear duct in each eye. The narrow tubes drain tears from the corner of each eye down the nose. Inflammation of the tear ducts is called dacryocystitis. This is a common health problem in rabbits.
What causes it?
Tears are produced continuously by tear glands around the eye. They protect the surface of the eye from injury and drying out. When the ducts are blocked or narrowed, tears can’t drain down the nose so they spill over the lower eyelid onto the face. This is called “epiphora”. The skin of the eyelid and face are constantly wet and become sore, there is usually fur loss and infection of the skin.
Dental disease is the most common cause of tear duct inflammation and obstruction. The tear ducts lie over the roots of the molar (back) teeth so if these roots become long they press on the tear ducts. Rabbits’ teeth grow continuously. If they are not grazing on grass or hay for 12-14 hours daily they are not worn down. An appropriate rabbit diet is 80% grass or hay, 5% pelleted food and 10-15% dark green leafy vegetables and the odd treat. This diet keeps their teeth short and prevent dental and tear duct disease.
Some rabbits have very short noses, their tear ducts tend to be curved and squashed by the shape of the skull. Obstruction of the tear duct is more common in these breeds. Rarely, rabbits have abnormally shaped lower eyelids so the ducts are not in the right position to be effective. Injury to the face can cause tear duct disease with eyelid wounds or skull fractures as these disrupt the tear duct.
The structures of the eye, tear duct and nose are all connected. Infection of the eye, nose or sinuses can spread to the tear duct and vice versa. In these cases there is often coloured discharge and crusting around the eye and sometimes the nose. The discharge can be white, grey, green or yellow and is usually too thick to drain in the tear ducts. Abscesses can form in the tear duct and cause swelling around the eye.
What happens to the rabbit?
The affected rabbit may hide away from you, eating less and appear depressed and lethargic. The eyelids and face usually appear wet, there may be matted fur and crusting around the eyes. A coloured discharge may be seen in the corner of the eye. In some cases the eyes are red and sore and as the rabbit rubs them they wipe discharge onto the inside of their front legs.
There may be a lump under the eye or along the nose as an abscess forms in the tear duct.
What can be done?
This disease cannot be treated at home. The cause of the tear duct obstruction must be found and treated.
Conjunctivitis or pink eye is usually caused by a bacterial infection, antibiotic and anti-inflammatory treatment will usually resolve this quickly. The eye and tear duct return to normal quickly. Sometimes a piece of hay, grass seed or other foreign body can get into the eye causing irritation, inflammation and infection. This can usually be treated simply by removal of the foreign body and topical treatment.
Similarly, if your rabbit has snuffles or another upper respiratory infection then treating that may resolve the tear duct obstruction. However, upper respiratory tract infection in the rabbit can be difficult to resolve completely and it may be chronic or resolve and recur.
In cases where pus and sludge are blocking the tear duct, your vet may flush the tear duct using a cannula and saline. This must be done gently and carefully and many rabbits require sedation for this procedure. The aim is to flush all the infected material down to the nose, opening up the tear duct. The nasolacrimal ducts of rabbits are very narrow so if they are significantly damaged this may need to be done a number of times. Your vet may send a sample of the fluid to the laboratory to grow the bacteria causing the disease and determine the right antibiotic to treat it.
Dental disease may be obvious on veterinary examination but a skull x-ray or CT scan is the only way to assess whether the roots are pressing on the tear ducts. Dental treatment can reduce the pressure on the nasolacrimal ducts. This may need to be performed every 3-12 months.
What can I do to protect my pet?
Check your rabbit’s face regularly. It should be clean, dry and comfortable with no abnormal lumps. The eye should be bright and clear with no abnormal discharge present. Regularly weigh your rabbit and assess their condition by checking that their ribs and spine are not too prominent.
Schedule a routine veterinary check every 6 months for a dental check. This can be done at vaccination then 6 months later. Keep your rabbit on a suitable diet to prevent tear duct obstruction and dental disease.
If cases of dacryocystitis are treated quickly then they are likely to resolve. However, if they are associated with a chronic condition such as snuffles or there is significant damage to the tear ducts the disease may need careful management in the long term.