Rabbits with runny eyes appear to have been crying: one or both cheeks may be wet, or just the fur underneath the eyes may be wet or just slightly damp and matted. There may be a thicker, white, stringy discharge from the eyes; all of these are signs that your rabbit needs to be seen by the veterinarian; any changes in your rabbit’s vision and/or the appearance of their eye or the surrounding area should be promptly evaluated by your rabbit-savvy veterinarian.
While runny eyes in and of themselves are not life threatening, they may be symptoms of a more serious underlying condition. Too, the continually wet fur and skin is an ideal environment for the growth of bacteria and fungi with resultant inflammation, fur loss and discomfort. The causes of watery eyes in rabbits are myriad and a correct diagnosis is required to effectively treat this condition.
Under normal conditions, tears are constantly being produced to bathe and protect the eye; the tears are drained away through the tear duct (the medical term for this is the ‘nasolacrimal canal’, for those of you who like to lord it over your friends how smart you are). The nasolacrimal canal is a tiny, thin tube with an opening at the corner of the eye nearest the nose. The tears empty into the nasal cavity (the correct term for an abnormal overflow of tears is 'epiphora', for you show-offs who still have any friends left).
A common reason for watery eyes is an obstruction of one or both of the tear ducts; even a partial blockage of the tear ducts will obviously restrict the drainage of the tears and cause them to overflow onto the cheek. Some rabbits, especially those with shortened faces (lops and dwarfs), are born with atypically narrow tear ducts that are more easily obstructed and make them more prone to chronic watery eyes.
Conditions that create pressure and resultant narrowing of the tear ducts include abscesses or other masses in the sinuses or other areas around the tear ducts, injuries/scarring to the face or eye, and even trauma from medical procedures. Dental issues can also impact the proper functioning of the lacrimal canal: the base of some of the rabbit’s molars are located just under the eyes. Abnormalities or infection and inflammation of these molars can cause pressure on the tear duct; even after the tooth is removed, the runny eyes may persist if the tear duct has become scarred.
Swelling of the mucous membranes lining the ducts can be also be caused by bacterial or fungal infections, including upper respiratory infections, conjunctivitis (infection of the mucous membrane of the eye) or infections of the tear duct itself. Certain infections can quickly spread to the jaw (forming an abscess) or to the respiratory tract. Your rabbit will need to be seen right away by a rabbit-savvy veterinarian for prescription of appropriate medications to treat the infection.
While normal rabbit tears are clear to slightly milky, if the discharge from the eye is opaque white, has the appearance of pus or stringy mucus, there may be an infection in the tear duct; this is known as dacryocystitis.
Yet another cause for epiphora, particularly in elderly rabbits or rabbits who have had long-term, chronically deficient diets is osteoporosis of the jaw. As with humans, bone density of rabbits decreases with age and this includes the upper and lower jaw of the rabbit. In a rabbit with osteoporosis in the jaw, the normal pressure of chewing can drive the roots of the deeper into the jawbone. In the upper jaw, the roots can intrude far enough to cause pressure on the tear ducts, resulting in watery eyes.
Generally speaking, the simplest obstruction to deal with is that of a blockage of cellular debris. The cells in the lining of the tear ducts constantly slough off and are then replaced (just like your own skin cells). If the dead cells that slough off manage to build up inside of the tear duct, they can partially block it, resulting in watery eyes and the need for your veterinarian to prescribe medications and/or flush the tear duct.
There are certainly other causes for epiphora beyond obstructions of the tear ducts, and your veterinarian will need to determine the cause of your rabbit’s epiphora. Your veterinarian will likely begin with simple diagnostics, examining the eye with an otoscope and testing your bunny’s sensitivity to light. Culture and sensitivity testing of the discharge may be necessary if bacterial infection is suspected. Xrays may be recommended to help visualize the condition of the jaw and sinuses.
Depending upon the diagnosis, antibiotic and/or anti-inflammatory eye drops may solve the problem, or perhaps a tear duct flush (or series of flushes) by your veterinarian. Dental or sinus infections will usually require oral medications.
Sometimes the problem recurs, and sometimes a permanent solution is not possible, if the tear ducts have permanent scarring or other non-remedial conditions. It is important to always keep the area around the eye clean. Rabbit tears are caustic, and matting of the fur around the eyes will hold the caustic fluid against the sensitive skin around the eyes; the delicate skin will become irritated and inflamed, and painful skin infections can result.
A warm, moist cloth against any mat under the eye may soften it so that eventually it can be removed. A better option is to diligently (but gently!) wipe the tears and debris that accumulate under the eyes on a daily basis so that they will not mat! In addition to being unsightly, those mats provide an environment for bacteria and fungi to grow.
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