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Glaucoma: Seeing Human Diseases Affect Our Pets


Pet Column for the week of March 12, 2007

Related information:

Services - Ophthalmology

Office of Public Engagement
2001 S. Lincoln Ave.
Urbana, Illinois 61802
Phone: 217/333-2907
Brookelyn Nitzkin
Information Specialist

Glaucoma is a common disease that affects the eyes of generally older individuals. This is caused by a rise in the pressures from within the eye, causing pain, visual deficits, and damage.

Dr. Ralph Hamor, veterinary ophthalmologist at the University of Illinois Veterinary Teaching Hospital in Urbana, Ill., reminds us that, "When a person is afflicted with this disease, they often visit the doctor's office with subtle eye deficits. By the time we notice it in our pets, the eye is usually fairly severely damaged."

Dogs are the most common animals afflicted with this disease. Although rare, cats and horses are also subject to glaucoma. Several dog breeds are predisposed to some of the problems associated with glaucoma. Cocker spaniels, terrier breeds, poodles, shar-peis, chow-chows, and basset hounds are some of the breeds that are most prone, although glaucoma can affect any breed. Although it may affect pets at any age, it is usually diagnosed in middle-aged dogs, approximately four to six years old.

Dr. Hamor notes that, "The eye can only respond in a few ways to disease. It gets red, cloudy, and painful." And this disease is no exception to that rule.

Intraocular pressures are the pressures that occur within the eye itself. This pressure is kept pretty constant as fluid is created and circulated into the eye. A drainage system drains equal amounts from the eye, leaving the organ at a steady pressure. If the fluid from within the eye can't escape, as is the case in primary glaucoma, pressures will rise and cause glaucoma.

The cause for primary glaucoma is that the drainage system is formed incorrectly or blocked for some reason. Secondary glaucoma occurs when an animal has a normal drainage system, but that drain is blocked. Secondary glaucoma can be due to a number of reasons, among which are chronic-inflammation of the eye, a tumor, or a systemic disease such as a fungus.

An important hallmark of glaucoma is that intraocular pressures will start to increase in the eye long before we notice any clinical signs. This is important because, if your pet is around five or six years old, it may be a good idea to have your pet's eye pressures checked during its yearly physical exam.

Treatments for this disease include a myriad of medical and surgical treatments. Secondary glaucoma is due to some other disease process which, when cleared up, may solve the glaucoma problem. For primary glaucoma, there are many anti-glaucoma drugs on the market. These drugs are generally good and will extend the vision of your pet. In fact, the medical drugs are the same as those used on humans. Unfortunately, this makes them very expensive and most pets end up requiring surgery anyway.

Dr. Hamor explains, "The objective of surgery is to find a way to turn off the faucet because the drain is simply not working." Trans-scleral lasers or internal lasers can be used to kill fluid-producing cells, which reduces the amount of fluid produced. There are also a number of shunting procedures which enable fluid to be diverted from the eye through a valve system to the sinuses or behind the eye.

"One eye will go first and, through no fault of the owner or veterinarian, that eye will most likely be in bad shape. The other eye is likely to follow, and if you want to extend the vision span for any real length of time, you will need surgery," says Dr. Hamor.

If your pet is blind as a result of glaucoma or any other eye disease, and it is still in pain from that disease, removal of the eye is a very humane and simple surgery to restore a pain free life to your pet.

Glaucoma is a relatively common disease for pets and humans alike. Fortunately, there are a number of treatments that can be considered for your pet.

For more information about glaucoma or treatment options for a pet suffering from this disease, consult your veterinarian.