What is Uveitis?
Uveitis is inflammation of some portion of the uveal tract of the eye, which consists of the iris, ciliary body and choroid. The term anterior uveitis refers to inflammation of the iris and ciliary body only, and the term posterior uveitis refers to inflammation of the choroid. Panuveitis refers to inflammation of all of these structures.
· Excessive tearing
· Excessive squinting
· Light sensitivity
· Corneal edema (blue haze to the eye)
· Decreased vision
· Color change to the iris (usually darker)
· Miotic (constricted) pupil
Uveitis can be caused by a variety of systemic infections, including diseases caused by bacteria, fungus, virus or protozoa. Examples include Toxoplasma gondii, Bartonella henselae, Cryptococcus and Histoplasma capsulatum. In cats, additional infectious causes include Feline leukemia virus (FeLV), Feline immunodeficiency virus (FIV) and Feline infectious peritonitis (FIP).
Uveitis is also commonly associated with cataracts (which are commonly seen in diabetic patients). Trauma to the lens or anterior chamber of the eye will also induce inflammation and uveitis. Other causes include vasculitis, radiation therapy, cancer, systemic hypertension and uveodermatologic syndrome. It is important to remember that the cause of the uveitis may not always be able to be identified, and is thus termed idiopathic.
Diagnosis of Uveitis
The clinical signs listed above, along with a low intraocular pressure, will assist your veterinarian in making the diagnosis of uveitis. The more difficult task is defining the cause. A thorough systemic evaluation, including a physical exam, complete blood count (CBC), chemistry panel and urinalysis should be completed to rule out causes of uveitis explained below. Additional diagnostic tests (clotting times, chest X-rays, titers for specific diseases) should be performed as determined by your veterinarian.
The goals of treatment of uveitis are to reduce the intraocular inflammation and to maintain vision in the eye.
The inflammation in the eye should be treated with topical anti-inflammatory eye drops. Topical atropine should also be used to keep the pupil dilated and alleviate pain. It is important to know that treatment may be lifelong.
Systemic therapy, if necessary, should be tailored based on the patient and the suspected cause of the uveitis. Your veterinarian will decide if other drugs (e.g. oral antibiotics, anti-inflammatories, anti-fungals, etc.) are necessary.
If not diagnosed in a timely manner, or if left untreated, uveitis can lead to very serious problems. Cataract formation, lens luxation, glaucoma, phthisis bulbi (shrinkage of the globe) and blindness are all potential complications of uveitis.
For more information on this subject, speak to the veterinarian who is treating your pet.