Overview of Anterior Uveitis in Cats
Anterior uveitis is inflammation that affects the front or anterior part of the eye called the uvea, which is the dark tissue of the eye that contains blood vessels. The iris – the tissue that makes up the pupil – is typically involved. The posterior part of the eye may or may not be affected.
The causes of anterior uveitis include: Immune mediated conditions in which the body attacks its own tissues Infections from viruses, parasites, fungi, bacteria, and protozoa Tumors or cancers Trauma or injury to the eye Metabolic disease elsewhere in the body that is affecting the eye Idiopathic, which means the cause is unknown Lens-induced, which is caused by the escape of lens protein into the eye fluid and is most frequently associated with cataracts
The eyes of cats are affected by more viruses than other animals. Such viruses include feline leukemia virus, feline immunodeficiency virus, and feline infectious peritonitis virus. The protozoal parasite, toxoplasmosis, is one of the most common causes of anterior uveitis in the cat.
Older cats are more likely to have tumors and indoor/outdoor pets are more likely to be exposed to infectious causes than pets housed strictly indoors. Also, in certain regions of the world specific infectious diseases are more common.
Anterior uveitis can be painful for your pet and may threaten vision. Just as important, this problem can also be a sign of a disease that is affecting the rest of the your pet’s body.
What to Watch ForRedness Tearing Squinting, especially in bright light A small or unevenly shaped pupil A cloudy or dull appearance in the front of the eye An unevenly colored iris – a normal yellow-green iris may be very red, develop brown areas or have spots within it
Diagnosis of Anterior Uveitis in Cats
Diagnostic tests are needed to recognize anterior uveitis, and exclude other diseases. Tests may include: Complete medical history and physical examination A complete examination of the eye with an ophthalmoscope, including the external portion, the front segment of the inside of the eye, and the back part of the eye. Tonometry, which is a measurement of pressure within the eye General blood tests, such as a complete blood count (CBC) and serum biochemical profile Specific blood tests for immune diseases, infectious agents or other systemic diseases Ultrasound, X-rays or aspirates, which are samples of fluid taken from inside the eye via a small needle
Treatment of Anterior Uveitis in Cats
Treatments for anterior uveitis may include symptomatic or specific therapy and surgical intervention: Symptomatic therapy, regardless of the cause of the anterior uveitis, is usually indicated. Topical treatments like drops or ointments placed on the eye and oral medications are designed to reduce pain and inflammation – like treating a headache with aspirin regardless of what is causing the headache. Specific therapy is directed if a cause for the anterior uveitis has been determined. Appropriate topical and/or oral drugs are prescribed and may include an anti-fungal drug or a drug that reduces immune mediated inflammation. Surgical intervention. In situations where there is a tumor or secondary complications (such as glaucoma) that cannot be controlled with medications, surgery to remove the eye may be necessary.
Home Care and Prevention
It is important that you follow your veterinarian’s instructions and learn to medicate your pet properly. It is not always easy to put medications into an animal’s eye, but it is imperative the medications be given.
Examine your pet’s eyes every day and look for subtle changes. See your veterinarian for follow-up appointments to re-examine eye.
You have some control over your pet’s environment. Cats can be protected from many of the infectious diseases that cause anterior uveitis by keeping them indoors.
Prevent trauma to eye; use caution when throwing balls or other objects.
In-Depth Information on Anterior Uveitis in Cats
A diagnosis of anterior uveitis simply means there is inflammation inside the eye. Numerous diseases can manifest as uveitis, so it can be difficult to diagnose the underlying cause. Some of the diseases mentioned below may be confined to the eye. However, in other cases, the condition may affect multiple parts of the body and the eye is but one aspect of disease. A pet may have either predominately ocular signs (those pertaining to the eye) or multisystemic signs such as weakness, lethargy, decreased appetite, coughing, fever or other problems.
Infectious causes of anterior uveitis are numerous. Some common causes include: Viral diseases. FIV (feline immunodeficiency virus), FeLV (feline leukemia virus), FIP (feline infectious peritonitis virus). Protozoal disease. Toxoplasmosis is a protozoan parasite that is more common in the cat than the dog . It is potentially a zoonotic disease, meaning that people can acquire this disease from cats that are shedding the parasite in bowel movements. If your cat is diagnosed with toxoplasmosis, it is essential to ask your veterinarian and physician about the risk. This is especially important for pregnant women, young children, elderly or immune-compromised individuals. Fungal diseases like blastomycosis, histoplasmosis, cryptococcosis, coccidiodomycosis, candidiasis. Different fungi are more common in dogs versus cats and in certain regions of the world. Cryptococcosis and histoplasmosis occur more often in the cat. Fungal diseases often involve the posterior (back) segment of the eye as well as the front. Many different strains of bacteria and different types of toxins. Sometimes a remote infection such as a uterine or kidney infection may lead to inflammation inside the eye. Many tick borne diseases cause uveitis in the dog, but rarely do so in the cat.
Other causes of anterior uveitis include: Tumors can cause anterior uveitis. The appearance varies, but the clinical signs of inflammation (uveitis) are common.
Lymphoma – The iris is generally thickened and there may be focal yellowish, white or pink discoloration.
Melanoma – The iris is generally thickened and darker brown than usual.
Adenoma or adenocarcinoma – Often appears as a pink white mass peaking through the pupil from behind the iris. Trauma. Any type of injury to the head or eye can cause a uveitis because the uvea contains numerous blood vessels, so secondary inflammation and “bruising” can occur. Metabolic diseases. Because the uvea is an extension of the body’s circulating blood system, many diseases that affect the body can have an impact on the eye. Examples include hypertension, elevated circulating proteins, and uremia. Lens-induced anterior uveitis may develop when cataracts are present. A cataract is an opacity of the lens. Lens-induced uveitis is more common in the dog, but may occur in the cat if some sort of penetrating trauma to the eye disrupts the lens. Immune-mediated diseases. In these diseases, the animal’s immune system “attacks” itself. These diseases tend to occur primarily in the dog, and include such conditions as thrombocytopenia, in which platelets are being attacked and destroyed, and hemolytic anemia, in which red blood cells are being attacked and destroyed by the immune system. Any uveitis associated with these conditions is a secondary effect. Secondary diseases complicating anterior uveitis may include glaucoma, cataract formation, blindness, and lens luxation.