Causes of Canine Glaucoma
The normal eye is filled with a fluid called aqueous humor. The amount of aqueous humor normally is carefully regulated to keep the eyeball in its proper shape. This happens from a very slow, but fairly continuous, exchange of fluid between the inner eye chambers and the blood in systemic circulation. This balance is disturbed in dogs with glaucoma, because aqueous humor is being produced faster than it can be removed, causing pressure to build up. Without treatment, the sustained elevated intraocular pressure will damage the retina and ultimately cause degenerative changes in the optic nerve as well, resulting in blindness.
There is no guaranteed way to prevent glaucoma in dogs. However, routine eye examinations can identify small changes in intraocular pressure, which can allow meaningful medical management before full-stage glaucoma develops. Dogs with glaucoma in one eye should be watched closely for development of the disease in the other eye. Most authorities recommend that dogs with primary glaucoma not be used in a breeding program. Acute-onset gluacoma due to trauma or some other eye disorder is a true medical emergency that requires immediate veterinary attention to reduce the pressure inside of the eye, which usually can be accomplished by use of intravenous medications.
Glaucoma is normally not life-threatening, but it definitely can adversely affect a dog’s quality of life. The prognosis for dogs suffering from glaucoma is variable. Most dogs will become blind, despite medical and/or surgical intervention. There is now some evidence that repeated forceful pulling on a dog’s neck collar increases the fluid pressure inside their eyes. Dogs predisposed to glaucoma or who have already developed glaucoma in one eye may do better walked on a harness rather than a collar.