Glaucoma is caused by Increased pressure within the eye. The increased pressure can rapidly cause blindness, and also pain.
It is hard to assess pain in animals, but we find that nearly all our patients are brighter, more active after having glaucoma relieved. Humans described the pain like having a bad headache; you can function, but not happily.
The normal pressure within the eye is 10 to 25 mm Hg. When the pressure is increased (usually > 30 mm Hg) a diagnosis of glaucoma is made. We measure the pressure in the eye (intraocular pressure - IOP) with a tonometer.
Once the eye becomes enlarged the eye is blind.
Causes for DOGS
Primary Glaucoma in some dogs the outflow of fluid from the eye is blocked by an abnormal drainage angle. Breeds that are affected by this include Basset Hounds, Cocker Spaniels, Australian Cattle Dogs, Fox Terriers, Poodles, Maltese Terriers and Golden Retrievers. Secondary Glaucoma is glaucoma that develops due to inflammation of the eye (uveitis), lens luxation, blood in the eye (hyphaema), or due to growths inside the eye.
Causes for CATS
Glaucoma is usually secondary to long standing inflammation in the eye, or to growths within the eye. We usually try intensive cortisone therapy and if the pressure does not decrease then eye removal or an intrascleral prosthesis is usually indicated.