Uveitis (soft eye)
Uveitis is an inflammation of the eye. It is inflammation of the middle layer of the eye, the uvea.
The most common form of uveitis is anterior uveitis (the anterior of the eye is an outer part of the eye from the iris, the colored part of the eye outward to the surface (cornea) – see the diagram of the eye) and is often called soft eye.
Causes of uveitis
In a dog with uveitis the cause cannot always be determined. Known causes include, a side effect of an immune reaction, infection, trauma to the eye and disruption of the lens. Occasionally uveitis is linked to diabetes.
Symptoms of uveitis
The symptoms of uveitis include pain, red eye, tearing, squinting, avoidance of light and the third eyelid being visible.
Sometimes the inflammation of the eye can make the eye look cloudy and/or the iris may start to look unevenly colored or reddish.
Often, but not always, the affected eye will feel softer than the other eye.
Uveitis can be serious, as well as being very painful for your dog, so prompt veterinary attention is important, to reduce the damage.
Getting treatment for the cause of the uveitis and relieving the symptoms is key to minimizing the likelihood of permanent effects.
Treatment of the symptoms will generally include medication that reduces inflammation, such as local application of steroid, as well as perhaps a course of steroid pills and NSAIDs (non-steroidal anti-inflammatories). Usually a drug, such as atropine, that will dilate the pupil is used. When there is inflammation the muscles of the iris may spasm, which is painful. Atropine and related drugs will paralyze the iris muscles, and reduce pain.
Other treatments of uveitis depends on the cause.
Immunosuppressant drugs will often be used since uveitis frequently has an autoimmune component. Generally, where a specific cause for the uveitis cannot be determined, the cause is thought to be immune. Consequently, many vets, unless a cause can be determined immediately on initial examination, will start some form of immune suppressing drug. For this reason steroids are often a drug of choice since they have both anti-inflammatory and immunosuppressant properties.
If the cause is infection, then some form of appropriate antibiotic or other treatment will be used.
Trauma and disruption of the lens of the eye may require surgery.
Glaucoma can occur as a result of increased pressure .
In some dogs the third eyelid (nictitating membrane) can come out of position.
Normally, when the eyelids are open the third eyelid is barely visible in the inner corner of the eye. When the third eyelid has a weak attachment it can prolapse (stick outward).
The prolapsing third eyelid exposes the tear gland that is associated with it. The exposed tear duct will get dry and irritated, and can easily get infected. The exposed tear duct starts to bulge out from under the third eyelid and will often become red. Hence the name cherry.
The bulging tear duct can irritate the eye and result in conjunctivitis.
Some breeds are a higher risk of cherry eye, including Boston Terriers, Bulldogs, Cocker Spaniels, Poodles, Beagles and Shar Pei. Dogs can get cherry eye at any age.
The third eyelid and tear gland can be repositioned surgically. The tear gland is attached by stitches into an area deep within the eye socket. This operation is quick and usually very successful. This surgery has replaced the old method of removing the eyelid and tear duct. The removal required that a dog had eye drops placed in their eye for the rest of their lives and be at a high risk of dry eye.
Occasionally the third eyelid can fold over on itself due to weakening or injury of the structures supporting the membrane. This can sometimes lead to irritation and infection. This condition can usually be fixed surgically.