Uveitis is inflammation within the eye. The structures affected are the iris (the colored part of the front of the eye) and the bloodvessel-rich layer that lies deep inside the eye, beneath the retina, called the choroid. Uveitis is a common condition in both cats anddogs and has many causes. Untreated uveitis can seriously damage the eye and even cause blindness.
Eye disorders that may cause uveitis include tumors, trauma such as being hit by a car, cataracts, severe corneal ulcers, andinfections. A wide variety of conditions that affect the blood vessels of the body in a general fashion (a situation called vasculitis)can also incite uveitis. These include immune-mediated diseases where the body’s own immune system inadvertently contributes toinflammation and tissue damage, high blood pressure, and some infectious diseases. In both dogs and cats, several fungaldiseases are known to cause uveitis.
In cats, feline leukemia virus infection, feline immunodeficiency virus infection, and felineinfectious peritonitis can all be associated with uveitis. In dogs, diseases such as brucellosis, leptospirosis, and heartworm infectioncan cause uveitis. Toxoplasmosis is another potential cause of uveitis. A great variety of other infectious diseases can have uveitisas one of the symptoms. Cats may develop a form of chronic uveitis where no underlying cause can be found. In summary, onceuveitis is identified by a veterinarian, a number of potential causes is possible and some tests need to be performed in order topinpoint the underlying cause and treat it.
Pets with uveitis may have variety of symptoms. The most noticeable to pet owners are redness of the eye, squinting, tearing, andavoidance of bright light. The eye may be painful. The clear part of the eye may become hazy or cloudy or, in severe cases, containwhite flecks (precipitates). Eventually blindness may occur.
Many eye disorders appear similar to uveitis, and uveitis occurs as a secondary condition in several eye and body-wide diseases.Your veterinarian will conduct a complete eye exam, including using an ophthalmoscope to look into the back of the eye. If uveitis orglaucoma is suspected, the intraocular pressure will be measured using an instrument called a tonometer. In uveitis, the intraocularpressure is lower than normal, while in glaucoma it is abnormally high. These and other tests help define the uveitis in an individualdog or cat, and give a clearer idea of treatment choices and outlook for improvement (prognosis).
Unless the cause of your pet’s uveitis is obvious, such as trauma, intraocular tumor, or cataract, your veterinarian will need to runadditional diagnostic tests to find the underlying disease. Blood tests can be used for detecting many infectious diseases. Chest orabdominal x-rays may be required to look for tumors or signs of fungal diseases. Ultrasound examination of the eye may berecommended in cases when the eye is too cloudy for a thorough examination of the eye with an ophthalmoscope or to check fortraumatic rupture of the eyeball or foreign bodies.
The long-term outlook (prognosis) for uveitis is very variable, depending upon the underlying cause. Some of the body-wideinfections that are associated with uveitis have a guarded prognosis; they can become life-threatening if the affected dog or catdoes not improve with treatment or may improve significantly and resolve completely. In the case of uveitis caused by trauma oranother treatable disease, the chance of resolution without serious damage to the eye depends upon the severity of theinflammation; some patients recover very well and regain normal vision and comfort, while others are left with some degree ofcomplications such as blindness, cataracts, glaucoma, and a shrunken eye.
Prompt and intensive treatment of uveitis is necessary to prevent damage to the eye. The underlying disease causing the uveitismust be controlled, if possible. Severe cases may require in-hospital treatment initially. Anti-inflammatory drugs are used to controlthe inflammation in the eye. Corticosteroids (cortisone-like drugs) are the most frequently used medications. Depending on theunderlying cause and the severity of the condition, these may be given as eye drops or eye ointments (applied to the eye severaltimes per day) or as an injection of long-lasting corticosteroids given under the conjunctiva (membrane covering the eye) where itwill be slowly absorbed. In some cases, corticosteroids or immunosuppressive drugs may be given as tablets by mouth. To reducepain, atropine eye drops or ointment maybe prescribed. Atropine causes the pupil to dilate, which lessens the pain of uveitis.Treatment of uveitis typically needs to continue for at least 2 months since the eye tissues often are slow to return to normal.
- When using eye drops or ointments to treat your pet, be sure to thoroughly wash your hands after treatment. This isespecially important with atropine medications, which will cause your pupils to dilate if you accidentally get them in youreyes, and antibiotics, which can cause severe allergic reactions in susceptible people.
- Keep track of your dog or cat’s symptoms and vision. Day-to-day fluctuations are common, and it is the trend over severaldays to weeks that determines the best course of treatment.
- Consider a referral to a veterinary ophthalmologist.