What Is Uveitis?
Uveitis is a form of ocular inflammation which affects the uvea or pigmented layers of the inside of the eye. The uveal tract includes the iris which forms the pupil, ciliary body which produces fluid in the eye and choroid (a vascular tissue which rests below the retina). Uveitis is a common feline disorder which has many causes which affect overall health in addition to eye health. The affects of uveitis can be mild to serious, leading to discomfort, loss of vision and even loss of an eye. If your cat presents with uveitis in one or both eyes, your ophthalmologist may recommend performing a number of tests to assess general health and infectious disease status.
What Are Some Clinical Signs of Uveitis?
Cats with uveitis can present with a number of clinical signs including squinting, decreased vision, conjunctivitis, elevated third eyelid, corneal edema, hyphema (blood inside the eye), constricted pupil (miosis), general inflammation of the front of the eye or change in color of the iris. Cats with chronic uveitis may also have glaucoma (elevated eye pressure), dilated pupil, cataract or lens luxation. Each individual patient can have a unique set of symptoms and the types of symptoms a cat has does not point to a specific underlying cause.
What Are Some Common Causes of Uveitis?
There are many causes for feline uveitis. Infectious diseases can include viral causes such as feline infectious peritonitis (FIP) and feline leukemia virus (FeLV). Common bacterial diseases affecting feline health include Toxoplasma gondii and Bartonella henselae. Fungal diseases that can affect cats include Histoplasma, Blastomyces, Cryptococcus and Coccidioides. These infections are diagnosed based on travel history, clinical signs and blood or urine tests. Cats with a history of trauma (either blunt force trauma or penetrating injury to the eye) can develop uveitis secondary to this injury. Certain types of cancer can also cause inflammation of the eyes, whether there is a tumor inside of the eye or spread (metastasis) from other areas of the body. Lymphosarcoma is a type of cancer which is most common to spread to the eye. Certain metabolic diseases can lead to retinal detachments or bleeding inside of the eye.
What Diagnostics Can Be Performed To Determine The Cause of Uveitis?
Based on a cat’s medical history and symptoms, a full systemic work-up may be recommended. This can include a
complete blood count and serum chemistry, urinalysis, and blood or urine tests specific to certain infectious diseases. Abdominal ultrasound or chest x-rays may be warranted to further assess general health. If there is a lot of inflammation at the front of the eye and it is hard to assess the back of the eye, your ophthalmologist may recommend an ocular ultrasound to help look for a mass or retinal detachment in the back of the eye. If a cause of uveitis is not discovered based on test results, a diagnosis of idiopathic uveitis (unidentifiable cause) is suspected.
What Are Different Treatment Options For Uveitis?
Treatment for feline uveitis will depend on the underlying cause. Oral antibiotics (doxycycline or clindamycin) or oral antifungal medications (fluconazole or itraconazole) are used for specific bacterial or fungal causes of uveitis. Topical atropine ointment may be used to dilate the pupil and decrease the risk of synechia (attachment of iris to the lens). Topical anti-inflammatory medications such as NSAIDs or steroid drops are commonly used based on the level of inflammation present. Oral pain medications or anti-inflammatories are sometimes prescribed as well.
Even if a cause is identified and treatment is started early, cats with uveitis are still predisposed to developing glaucoma, cataracts, decreased vision or even blindness from the complications of uveitis. The goals with treatment are to prevent these complications, but also to identify and treat any underlying systemic disease which could also affect general health and comfort longterm.