Uveitis & Glaucomaby Betty Lewis
Chow chows are genetically predisposed to glaucoma. So are samoyeds, cocker spaniels, poodles and Siberians.
Uveitis is an inflammation of the eye's uveal tract and glaucoma is a buildup of pressure in the eye damaging the optic nerve. Both are serious conditions that need to be addressed as early as possible to minimize the impact on Duke's vision. Regular veterinary visits are imperative for a dog with glaucoma.
The What of Uveitis
Your pup's eye is comprised of three layers, and when Duke has uveitis, the middle layer of his eye is affected. The middle layer has the uveal tract, rich in blood vessels, as well as the iris, the choroid and the ciliary body connecting the two. The blood vessels in the uveal tract make it vulnerable to inflammation and disease. If Duke's ciliary body is inflamed, he has cyclitis; if the choroid is inflamed, he has choroiditis; if all parts of the uveal tract are inflamed, he has uveitis or pan-uveitis. Trauma is one common cause of uveitis; infections, high blood pressure, metabolic disorders, toxemia or autoimmune disease also inflame the uveal tract. If you notice severe reddening or cloudiness in Duke's eye, he may have some inflammation in his uveal tract. Other symptoms include excessive tearing, avoiding bright lights, keeping the eye shut and bleeding into the eye.
Calming The Uveal Tract
The vet will give Duke a thorough exam and measure his eye pressure. A low intraocular pressure, or IOP, is common with uveitis; the IOP test is a safe and easy test usually done in the vet's office. It's important to treat uveitis to prevent glaucoma and scarring of the uveal structures. Treatment includes addressing the root cause of the uveitis and medication to control inflammation in the uveal tract. Aspirin and corticosteroids are especially helpful for minimizing inflammation.
Glaucoma: High IOP
When there's too much pressure on the eye, the eye's fluid can't drain properly, leading to glaucoma. If Duke has primary glaucoma, he was born with an abnormality in his eye's structure causing the buildup of fluid. Perhaps he suffered a trauma, or has a condition such as cataracts or uveitis, causing a problem with his eye's fluid flow and draining, resulting in secondary glaucoma. Untreated, glaucoma can cause lasting damage to the optic nerve, leading to blindness. The first hint of trouble is usually in the form of an enlarged pupil that doesn't constrict in bright light. As well, the eye's blood vessels are often inflamed and very red. Other signs of glaucoma include blinking, the eyeball receding back into the head, cloudy appearance at the front of the eye and visible inflammatory debris in the eye. As the disease progresses, you may notice an obvious loss in vision and that his eyeball is enlarged.
Don't Delay the Vet Visit
Glaucoma can be misdiagnosed as an allergy or conjunctivitis, so Duke's intraocular pressure should be checked to confirm the condition. Speed is of the essence in diagnosis because glaucoma can develop quickly, leading to vision loss. A pressure reading greater than 25 indicates glaucoma is present; at 50, the optic nerve and retina are permanently damaged; at greater than 50, vision has been -- or will be -- permanently lost. Treatment is aimed at reducing the amount of fluid the eye produces and the amount of pressure in the eye, as well as increasing how much fluid drains from the eye. Of course, the vet will also give Duke some pain relief from his condition. A variety of medications perform this checklist of tasks, though it's not always a successful battle. Sometimes surgery helps, and occasionally, removing the eye is ultimately the best option for your pup.
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